dm log userspace transfer: match wait_for_completion_timeout return type

Return type of wait_for_completion_timeout() is unsigned long not int.
An appropriately named unsigned long is added and the assignment fixed.

Signed-off-by: Nicholas Mc Guire <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-log-userspace-transfer.c

···
 			 char *rdata, size_t *rdata_size)
 {
 	int r = 0;
+	unsigned long tmo;
 	size_t dummy = 0;
 	int overhead_size = sizeof(struct dm_ulog_request) + sizeof(struct cn_msg);
 	struct dm_ulog_request *tfr = prealloced_ulog_tfr;
···
 		goto out;
 	}
 
-	r = wait_for_completion_timeout(&(pkg.complete), DM_ULOG_RETRY_TIMEOUT);
+	tmo = wait_for_completion_timeout(&(pkg.complete), DM_ULOG_RETRY_TIMEOUT);
 	spin_lock(&receiving_list_lock);
 	list_del_init(&(pkg.list));
 	spin_unlock(&receiving_list_lock);
-	if (!r) {
+	if (!tmo) {
 		DMWARN("[%s] Request timed out: [%u/%u] - retrying",
 		       (strlen(uuid) > 8) ?
 		       (uuid + (strlen(uuid) - 8)) : (uuid),