spi: st-ssc4: Remove duplicate code to test unsupported mode bits

spi_setup() will test unsupported mode bits before calling spi->master->setup.
Thus remove duplicate code to test unsupported mode bits in spi_st_setup().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed