FS-Cache: Add missing initialization of ret in cachefiles_write_page()

fs/cachefiles/rdwr.c: In function ‘cachefiles_write_page’:
fs/cachefiles/rdwr.c:882: warning: ‘ret’ may be used uninitialized in
this function

If the jump to label "error" is taken, "ret" will indeed be
uninitialized, and random stack data may be printed by the debug code.

Fixes: 102f4d90 ("FS-Cache: Handle a write to the page immediately beyond the EOF marker")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/cachefiles/rdwr.c

@@ -879,7 +879,7 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
 	loff_t pos, eof;
 	size_t len;
 	void *data;
-	int ret;
+	int ret = -ENOBUFS;
 
 	ASSERT(op != NULL);
 	ASSERT(page != NULL);