omap2_mcspi: Flush posted writes

mcspi_write_chconf0 is used to control rx/tx triggering.
Post-write flushing is needed to get the immediate effect.

Signed-off-by: Roman Tereshonkov <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

drivers/spi/omap2_mcspi.c

···
 
 	cs->chconf0 = val;
 	mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, val);
+	mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 }
 
 static void omap2_mcspi_set_dma_req(const struct spi_device *spi,