spi: pl022: Remove set but not used variable 'chip'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/spi/spi-pl022.c: In function 'do_polling_transfer':
drivers/spi/spi-pl022.c:1493:20: warning:
 variable 'chip' set but not used [-Wunused-but-set-variable]
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-pl022.c

@@ -1490,10 +1490,8 @@ static void do_polling_transfer(struct pl022 *pl022)
 	struct spi_message *message = NULL;
 	struct spi_transfer *transfer = NULL;
 	struct spi_transfer *previous = NULL;
-	struct chip_data *chip;
 	unsigned long time, timeout;
 
-	chip = pl022->cur_chip;
 	message = pl022->cur_msg;
 
 	while (message->state != STATE_DONE) {