firewire: core: fw_iso_resource_manage: fix error handling

If the bandwidth allocation fails, the error must be returned in
*channel regardless of whether the channel allocation succeeded.
Checking for c >= 0 is not correct if no channel allocation was
requested, in which case this part of the code is reached with
c == -EINVAL.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/core-iso.c

@@ -331,8 +331,9 @@ void fw_iso_resource_manage(struct fw_card *card, int generation,
 	if (ret < 0)
 		*bandwidth = 0;
 
-	if (allocate && ret < 0 && c >= 0) {
-		deallocate_channel(card, irm_id, generation, c, buffer);
+	if (allocate && ret < 0) {
+		if (c >= 0)
+			deallocate_channel(card, irm_id, generation, c, buffer);
 		*channel = ret;
 	}
 }