[CIFS] Fix cifs update of page cache. Write at correct offset when out of memory
and add_to_page_cache fails.  

Thanks to Shaggy for pointing out the fix.

Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Shaggy (shaggy@us.ibm.com)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index dde2d25..30ab70c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1352,6 +1352,8 @@
 				      GFP_KERNEL)) {
 			page_cache_release(page);
 			cFYI(1, ("Add page cache failed"));
+			data += PAGE_CACHE_SIZE;
+			bytes_read -= PAGE_CACHE_SIZE;
 			continue;
 		}