mm/filemap.c: use vmf_error()

These codes can be replaced with new inline vmf_error().

Link: http://lkml.kernel.org/r/20180927171411.GA23331@jordon-HP-15-Notebook-PCSigned-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

@@ -2596,9 +2596,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
 	 * system is low on memory, or a problem occurs while trying
 	 * to schedule I/O.
 	 */
-	if (error == -ENOMEM)
-		return VM_FAULT_OOM;
-	return VM_FAULT_SIGBUS;
+	return vmf_error(error);
 
 page_not_uptodate:
 	/*