mtd: rawnand: mxc: 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.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240604212919.5038-5-wsa+renesas@sang-engineering.com

drivers/mtd/nand/raw/mxc_nand.c

@@ -457,14 +457,14 @@ static int wait_op_done(struct mxc_nand_host *host, int useirq)
 		return 0;
 
 	if (useirq) {
-		unsigned long timeout;
+		unsigned long time_left;
 
 		reinit_completion(&host->op_completion);
 
 		irq_control(host, 1);
 
-		timeout = wait_for_completion_timeout(&host->op_completion, HZ);
-		if (!timeout && !host->devtype_data->check_int(host)) {
+		time_left = wait_for_completion_timeout(&host->op_completion, HZ);
+		if (!time_left && !host->devtype_data->check_int(host)) {
 			dev_dbg(host->dev, "timeout waiting for irq\n");
 			ret = -ETIMEDOUT;
 		}