mm/util: use offset_in_page macro

linux/mm.h provides offset_in_page() macro.  Let's use already predefined
macro instead of (addr & ~PAGE_MASK).

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/util.c

@@ -309,7 +309,7 @@ unsigned long vm_mmap(struct file *file, unsigned long addr,
 {
 	if (unlikely(offset + PAGE_ALIGN(len) < offset))
 		return -EINVAL;
-	if (unlikely(offset & ~PAGE_MASK))
+	if (unlikely(offset_in_page(offset)))
 		return -EINVAL;
 
 	return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);