powerpc/mpic_msgr: fix offset error when setting mer register

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/mpic_msgr.c b/arch/powerpc/sysdev/mpic_msgr.c
index dc1cfe3..483d8fa 100644
--- a/arch/powerpc/sysdev/mpic_msgr.c
+++ b/arch/powerpc/sysdev/mpic_msgr.c
@@ -228,7 +228,7 @@
 
 		reg_number = block_number * MPIC_MSGR_REGISTERS_PER_BLOCK + i;
 		msgr->base = msgr_block_addr + i * MPIC_MSGR_STRIDE;
-		msgr->mer = msgr->base + MPIC_MSGR_MER_OFFSET;
+		msgr->mer = (u32 *)((u8 *)msgr->base + MPIC_MSGR_MER_OFFSET);
 		msgr->in_use = MSGR_FREE;
 		msgr->num = i;
 		raw_spin_lock_init(&msgr->lock);