spi: sun4i: 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>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20240430114142.28551-7-wsa+renesas@sang-engineering.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-sun4i.c

@@ -206,7 +206,8 @@ static int sun4i_spi_transfer_one(struct spi_controller *host,
 				  struct spi_transfer *tfr)
 {
 	struct sun4i_spi *sspi = spi_controller_get_devdata(host);
-	unsigned int mclk_rate, div, timeout;
+	unsigned int mclk_rate, div;
+	unsigned long time_left;
 	unsigned int start, end, tx_time;
 	unsigned int tx_len = 0;
 	int ret = 0;
@@ -327,10 +328,10 @@ static int sun4i_spi_transfer_one(struct spi_controller *host,
 
 	tx_time = max(tfr->len * 8 * 2 / (tfr->speed_hz / 1000), 100U);
 	start = jiffies;
-	timeout = wait_for_completion_timeout(&sspi->done,
+	time_left = wait_for_completion_timeout(&sspi->done,
 						msecs_to_jiffies(tx_time));
 	end = jiffies;
-	if (!timeout) {
+	if (!time_left) {
 		dev_warn(&host->dev,
 			 "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
 			 dev_name(&spi->dev), tfr->len, tfr->speed_hz,