spi: omap-100k: Remove set but not used variable 'dataH'

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

drivers/spi/spi-omap-100k.c: In function spi100k_read_data:
drivers/spi/spi-omap-100k.c:140:6: warning: variable dataH set but not used [-Wunused-but-set-variable]

It is not used since commit 35c9049b ("Add OMAP spi100k driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1570581437-104549-2-git-send-email-zhengbin13@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-omap-100k.c

@@ -128,7 +128,7 @@ static void spi100k_write_data(struct spi_master *master, int len, int data)
 
 static int spi100k_read_data(struct spi_master *master, int len)
 {
-	int dataH, dataL;
+	int dataL;
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 
 	/* Always do at least 16 bits */
@@ -146,7 +146,7 @@ static int spi100k_read_data(struct spi_master *master, int len)
 	udelay(1000);
 
 	dataL = readw(spi100k->base + SPI_RX_LSB);
-	dataH = readw(spi100k->base + SPI_RX_MSB);
+	readw(spi100k->base + SPI_RX_MSB);
 	spi100k_disable_clock(master);
 
 	return dataL;