mm: make maddr __iomem

sparse output following warnings.

mm/memory.c:2936:8: warning: incorrect type in assignment (different address spaces)
mm/memory.c:2936:8:    expected void *maddr
mm/memory.c:2936:8:    got void [noderef] <asn:2>

cleanup here.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -2966,7 +2966,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 {
 	resource_size_t phys_addr;
 	unsigned long prot = 0;
-	void *maddr;
+	void __iomem *maddr;
 	int offset = addr & (PAGE_SIZE-1);
 
 	if (follow_phys(vma, addr, write, &prot, &phys_addr))