functionControl internal option is documented but only the misspelled functonControl works

`IGCInternalOptions.td:139` on master defines `functonControl`, while the comment on line 138 documents the option as `-ze-intel-functionControl`. The correctly spelled form is defined nowhere, and unknown internal options are accepted without a diagnostic, so it silently does nothing.

ocloc 26.27.39122.11, `-device dg2`. Still present on master at 321f3610.

```c
__attribute__((noinline)) int helper(global int *p, int i) { return p[i] * 3 + i; }
kernel void k(global int *o, global int *p) {
int i = get_global_id(0);
o[i] = helper(p, i) + helper(p, i + 1);
}
```

| `-internal_options` | resulting `fc_dg2.bin` |
|---|---|
| none | 5736 bytes |
| `-cl-intel-functonControl 1` | 5952 bytes |
| `-cl-intel-functionControl 1` | 5736 bytes, byte identical to none |

I have a patch adding the documented spelling as an alias so the existing one keeps working, and can open a PR.

Start at IGCInternalOptions.td:138-139 and inspect how internal option names are declared and consumed. Reproduce the issue with ocloc on dg2 using the supplied kernel, comparing fc_dg2.bin for no option and each spelling. Done means the documented spelling is recognized while the existing spelling remains compatible.

Written by the indexing model from the issue text.