mm/mlock.c: drop unneeded initialization in munlock_vma_pages_range()

Before usage page pointer initialized by NULL is reinitialized by
follow_page_mask().  Drop useless init of page pointer in the beginning
of loop.
Signed-off-by: Alexey Klimov <klimov.linux@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mlock.c

@@ -425,7 +425,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma,
 	vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
 
 	while (start < end) {
-		struct page *page = NULL;
+		struct page *page;
 		unsigned int page_mask;
 		unsigned long page_increm;
 		struct pagevec pvec;