spi: synquacer: wait until slave is deselected

synquacer_cs_set() function does not wait the chip select
is deasserted when the driver sets the DMSTOP to deselect
the slave.
This commit checks the Slave Select Released(SRS) bit to wait
until the slave is deselected.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Signed-off-by: Satoru Okamoto <okamoto.satoru@socionext.com>
Acked-by: Jassi Brar <jaswinder.singh@linaro.org>
1 file changed