PM: hibernate: Do not initialize error in swap_write_page()

'error' first receives the function result before it is used, and it
does not need to be assigned a value during definition.

Signed-off-by: Li zeming <[e-mail]>
[ rjw: Subject rewrite ]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

kernel/power/swap.c

···
 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 		struct hib_bio_batch *hb)
 {
-	int error = 0;
+	int error;
 	sector_t offset;
 
 	if (!handle->cur)