mm/mmap.c: remove redundant statement "error = -ENOMEM"

It is still a little better to remove it, although it should be skipped
by "-O2".

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>=0A=
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mmap.c

@@ -1562,7 +1562,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	}
 
 	/* Clear old maps */
-	error = -ENOMEM;
 	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
 			      &rb_parent)) {
 		if (do_munmap(mm, addr, len))