spi: add power control when set_cs_timing

As to set_cs_timing takes effect immediately, power spi
is needed when call spi_set_cs_timing.

Signed-off-by: leilk.liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210207030953.9297-2-leilk.liu@mediatek.com


Signed-off-by: Mark Brown <broonie@kernel.org>