spi: rspi: Merge rspi_send_pio() and rspi_receive_pio()
rspi_send_pio() and rspi_receive_pio() are very similar:
- the former only sends data, using TX Only Mode,
- the latter sends and receives full duplex data to/from the hardware,
but uses dummy transmit data.
Merge them into rspi_transfer_out_in(), now supporting full duplex if
needed.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
(cherry picked from commit
8449fd76deb9ac67a15a6fb8ead7bb4595d019d2)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>