[PATCH v2] rapidio: fix unused variable warning in rio_cm.c

[Anirudh Rayabharam <mail@anirudhrb.com>]

GCC produces an unused variable warning for 'rc':

	drivers/rapidio/rio_cm.c: In function ‘rio_txcq_handler’:
	drivers/rapidio/rio_cm.c:673:7: warning: variable ‘rc’ set but
	not used [-Wunused-but-set-variable]

The return value of rio_add_outb_message() is assigned to 'rc' but it
is never used. Fix this warning by logging an error if 'rc' is non-zero.

Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
---

Changes in v2:
Log an error instead of just removing 'rc'.

v1: https://lore.kernel.org/lkml/20210501055018.9244-1-mail@anirudhrb.com/

---
 drivers/rapidio/rio_cm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/rapidio/rio_cm.c b/drivers/rapidio/rio_cm.c
index 50ec53d67a4c..971a36f1a23a 100644
--- a/drivers/rapidio/rio_cm.c
+++ b/drivers/rapidio/rio_cm.c
@@ -677,6 +677,11 @@ static void rio_txcq_handler(struct cm_dev *cm, int slot)
 			cm->tx_buf[cm->tx_slot] = req->buffer;
 			rc = rio_add_outb_message(cm->mport, req->rdev, cmbox,
 						  req->buffer, req->len);
+			if (rc) {
+				riocm_error("Failed to add msg to tx queue (err=%d)",
+						rc);
+			}
+
 			kfree(req->buffer);
 			kfree(req);
 
-- 
2.26.2