change MAX_CH_AMP on WiiU
#ifdef GB_INTERNAL
/* Divides nicely and never overflows with 4 channels and 8 (1-8) volume levels */
+#ifdef WIIU
+#define MAX_CH_AMP 0x1FE0 / 4
+#else
#define MAX_CH_AMP 0x1FE0
+#endif
#define CH_STEP (MAX_CH_AMP/0xF/8)
#endif
