Match the rest of mcardGCN.c

[cadmic]

Sorry for the large PR, a lot of the code seems pretty repetitive. I'll try to do cleanups in a follow-up PR, namely:

• give names for constants
• use true/false consistently for boolean variables (like saveToggle)
• make a macro for (u32)(x + 8187) / 8188

[Yanis002]

I think a lot of those values are probably macros from the SDK
otherwise I think what I commented here are things that are planned for cleanup, nice work!