spi/fsl-dspi: Remove some coding sytle not in standard

Remove some coding sytle not in standard in former code.
Signed-off-by: NChao Fu <b44548@freescale.com>
Reviewed-by: NXiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: NMark Brown <broonie@linaro.org>