powerpc/pseries: Update MAX_HCALL_OPCODE to reflect page coalescing

When page coalescing support was added recently, the MAX_HCALL_OPCODE
define was not updated for the newly added H_GET_MPP_X hcall.
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/hvcall.h

@@ -236,7 +236,7 @@
 #define H_HOME_NODE_ASSOCIATIVITY 0x2EC
 #define H_BEST_ENERGY		0x2F4
 #define H_GET_MPP_X		0x314
-#define MAX_HCALL_OPCODE	H_BEST_ENERGY
+#define MAX_HCALL_OPCODE	H_GET_MPP_X
 
 #ifndef __ASSEMBLY__