unitialized return value in mm/mlock.c: __mlock_vma_pages_range()

Fix an unitialized return value when compiling on parisc (with CONFIG_UNEVICTABLE_LRU=y):
mm/mlock.c: In function `__mlock_vma_pages_range':
mm/mlock.c:165: warning: `ret' might be used uninitialized in this function

Signed-off-by: Helge Deller <[e-mail]>
[ It isn't ever really used uninitialized, since no caller should ever
call this function with an empty range. But the compiler is correct
that from a local analysis standpoint that is impossible to see, and
fixing the warning is appropriate. ]
Signed-off-by: Linus Torvalds <[e-mail]>

mm/mlock.c

···
 	unsigned long addr = start;
 	struct page *pages[16]; /* 16 gives a reasonable batch */
 	int nr_pages = (end - start) / PAGE_SIZE;
-	int ret;
+	int ret = 0;
 	int gup_flags = 0;
 
 	VM_BUG_ON(start & ~PAGE_MASK);