slimbus: messaging: use 'time_left' variable with wait_for_completion_timeout()

There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:

	timeout = wait_for_completion_timeout(...)
	if (!timeout) return -ETIMEDOUT;

with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.

Fix to the proper variable type 'unsigned long' while here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20240902141004.70048-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Wolfram Sang

drivers/slimbus/messaging.c

@@ -111,7 +111,8 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
 	bool need_tid = false, clk_pause_msg = false;
-	int ret, timeout;
+	int ret;
+	unsigned long time_left;
 
 	/*
 	 * do not vote for runtime-PM if the transactions are part of clock
@@ -151,9 +152,9 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 	if (!ret && need_tid && !txn->msg->comp) {
 		unsigned long ms = txn->rl + HZ;
 
-		timeout = wait_for_completion_timeout(txn->comp,
-						      msecs_to_jiffies(ms));
-		if (!timeout) {
+		time_left = wait_for_completion_timeout(txn->comp,
+							msecs_to_jiffies(ms));
+		if (!time_left) {
 			ret = -ETIMEDOUT;
 			slim_free_txn_tid(ctrl, txn);
 		}