Incorrect spacing on gcc asm command.

## Information

Line 12 of asm/gcc.vim is incorrect:

- It is currently: \ . '-iquote %s:h'

- It is missing a leading space and should be: \ . ' -iquote %s:h'

You can see the error in ALEInfo as "-o /dev/null-iquote".

**VIM version**

Latest version as shown in git.

Operating System: Debian Bookworm.

## What went wrong

When editing an asm file I get spurious errors.

### :ALEInfo

Current Filetype: asm
Available Linters: ['gcc', 'llvm_mc']
Enabled Linters: ['gcc']
Ignored Linters: []
Suggested Fixers:
'remove_trailing_lines' - Remove all blank lines at the end of a file.
'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.

Linter Variables:
" Press Space to read :help for a setting
let g:ale_asm_gcc_executable = 'gcc'
let b:ale_asm_gcc_executable = '/usr/bin/avr-gcc'
let g:ale_asm_gcc_options = '-Wall'
let b:ale_asm_gcc_options = '-c -g -O -x assembler -DF_CPU=16000000UL -mmcu=atmega328p -isystem /usr/lib/avr/include -isystem /usr/lib/avr/include/avr -o /dev/null -iquote /asm_test/src/src/asm -Wa,-L'
let g:ale_asm_llvm_mc_executable = 'llvm-mc'
let g:ale_asm_llvm_mc_options = ''

Global Variables:
" Press Space to read :help for a setting
let g:ale_cache_executable_check_failures = v:null
let g:ale_change_sign_column_color = 0
let g:ale_command_wrapper = ''
let g:ale_completion_delay = v:null
let g:ale_completion_enabled = 0
let g:ale_completion_max_suggestions = v:null
let g:ale_disable_lsp = 'auto'
let g:ale_echo_cursor = 1
let g:ale_echo_msg_error_str = 'Error'
let g:ale_echo_msg_format = '%code: %%s'
let g:ale_echo_msg_info_str = 'Info'
let g:ale_echo_msg_warning_str = 'Warning'
let g:ale_enabled = 1
let b:ale_enabled = 1
let g:ale_fix_on_save = 1
let g:ale_fixers = {'*': ['remove_trailing_lines', 'trim_whitespace']}
let g:ale_history_enabled = 1
let g:ale_info_default_mode = 'preview'
let g:ale_history_log_output = 1
let g:ale_keep_list_window_open = 0
let g:ale_lint_delay = 200
let b:ale_lint_delay = 200
let g:ale_lint_on_enter = 1
let g:ale_lint_on_filetype_changed = 1
let g:ale_lint_on_insert_leave = 1
let g:ale_lint_on_save = 1
let g:ale_lint_on_text_changed = 'never'
let g:ale_linter_aliases = {}
let g:ale_linters = {}
let b:ale_linters = ['gcc']
let g:ale_linters_explicit = 0
let g:ale_linters_ignore = {}
let g:ale_list_vertical = 0
let g:ale_list_window_size = 10
let g:ale_loclist_msg_format = '%code: %%s'
let g:ale_max_buffer_history_size = 20
let g:ale_max_signs = -1
let g:ale_maximum_file_size = v:null
let g:ale_open_list = 0
let g:ale_pattern_options = v:null
let g:ale_pattern_options_enabled = v:null
let g:ale_root = {}
let g:ale_set_balloons = 1
let g:ale_set_highlights = 1
let g:ale_set_loclist = 1
let g:ale_set_quickfix = 0
let g:ale_set_signs = 1
let g:ale_sign_column_always = 1
let g:ale_sign_error = 'E'
let g:ale_sign_info = 'I'
let g:ale_sign_offset = 1000000
let g:ale_sign_style_error = 'E'
let g:ale_sign_style_warning = 'W'
let g:ale_sign_warning = 'W'
let g:ale_sign_highlight_linenrs = 0
let g:ale_type_map = {}
let g:ale_use_neovim_diagnostics_api = 0
let g:ale_use_global_executables = v:null
let g:ale_virtualtext_cursor = 'all'
let g:ale_warn_about_trailing_blank_lines = 1
let g:ale_warn_about_trailing_whitespace = 1

Command History:

(executable check - success) /usr/bin/avr-gcc
(finished - exit code 1) ['/bin/bash', '-c', '''/usr/bin/avr-gcc'' -x assembler -o /dev/null-iquote ''/ext/data/xen-dev/chiller_control/CC.c/asm_test/src/src/asm'' -c -g -O -x assembler -DF_CPU=16000000UL -mmcu=atmega328p -isystem /usr/lib/avr/include -isystem /usr/lib/avr/include/avr -o /dev/null -iquote /ext/data/zen-dev/chillder_control/CC.c/asm_test/src/src/asm -Wa,-L - < ''/tmp/vAaLrV8/0/aes.S''']

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avr-gcc: fatal error: cannot specify -o with -c, -S or -E with multiple files
compilation terminated.
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