spi: mediatek: remove needless pair of writel()/readl()

It's not need to re-read and re-write SPI_CMD_REG, so remove it.

Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed