UNIF: Fix potential crash when accessing non-existing rom banks

- As stated, prevent a potential crash on some certain roms using split rom banks. This is done by counting the number of prg/chr banks loaded and using this as limit count during mapper bank switching.
- Update related boards.

src/cart.c

@@ -53,6 +53,9 @@ static int PRGram[32];
 uint8 *PRGptr[32];
 uint8 *CHRptr[32];
 
+uint32 PRGchip_max;
+uint32 CHRchip_max;
+
 uint32 PRGsize[32];
 uint32 CHRsize[32];
 
@@ -104,6 +107,8 @@ void ResetCartMapping(void) {
 	for (x = 0; x < 8; x++) {
 		MMC5SPRVPage[x] = MMC5BGVPage[x] = VPageR[x] = nothing - 0x400 * x;
 	}
+	PRGchip_max = 0;
+	CHRchip_max = 0;
 }
 
 void SetupCartPRGMapping(int chip, uint8 *p, uint32 size, int ram) {