Fix AVRISP-MKII clone project's TPI Chip Erase command processing - ensure erase location is the high byte in the given address space, check NVMBUSY for completion rather than the NVM Bus Enable bit.

Change If-Else chains over to switch statements in XPROGProtocol.c for clarity.

Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.h

@@ -131,7 +131,7 @@
 		#define TPI_NVMENABLE_KEY          (uint8_t[]){0x12, 0x89, 0xAB, 0x45, 0xCD, 0xD8, 0x88, 0xFF}
 
 		#define TPI_POINTER_INDIRECT       0
-		#define TPI_POINTER_INDIRECT_PI    (1 << 2)
+		#define TPI_POINTER_INDIRECT_PI    4
 		
 	/* Function Prototypes: */
 		void    XPROGTarget_EnableTargetPDI(void);