VBA-M - core remap results in A and B swapped

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

Using the core button remapping under the "quick menu" doesn't give correct results with VBA-M.

Expected behavior

button remapped to A results in A input, button remapped to B results in a B input

Actual behavior

works correctly with defaults, after remapping A gives B input and B gives A input

Steps to reproduce the bug

1. Delete the core remap file if present
2. Load Gameboy game in VBA-M core (tested with Pokemon Blue)
3. Using Quick Menu>Controls, change core remap settings from defaults to place GB A on gamepad B and GB B on gamepad Y

Bisect Results

[Try to bisect and tell us when this started happening]

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.8.5/532fd88e2f

Environment information

• OS: Windows 7 x64

Reproduce with the VBA-M core and Pokemon Blue using Quick Menu > Controls, after deleting any existing core remap file. Trace the core remap handling from the reported A/B assignments; done means mapping gamepad B to GB A and gamepad Y to GB B produces the corresponding inputs instead of swapping them.