This generated a warning on GCC about the operation being potentially undefined (-Wsequence-point). I'm not sure if that was actually the case, but either way it is a mistake.
We should expose Enable Controller Input and the turbo settings for
GBA just like we do for GameCube controllers and Wii Remotes.
I just forgot about it when implementing the GBA TAS input window.
When emulated GBAs were added to Dolphin, it was possible to control them
using the GC TAS input window. (Z was mapped to Select.) Unaware of this,
I broke the functionality in b296248.
To make it possible to control emulated GBAs using TAS input again,
I'm adding a proper TAS input window for GBAs, with a real Select button
and no analog controls.