spi: spi-geni-qcom: Select FIFO mode for chip select

spi: spi-geni-qcom: Select FIFO mode for chip select

Spi geni driver switches between FIFO and DMA modes based on xfer length.
FIFO mode relies on M_CMD_DONE_EN interrupt for completion while DMA mode
relies on XX_DMA_DONE.
During dynamic switching, if FIFO mode is chosen, FIFO related interrupts
are enabled and DMA related interrupts are disabled. And viceversa.
Chip select shares M_CMD_DONE_EN interrupt with FIFO to check completion.
Now, if a chip select operation is preceded by a DMA xfer, M_CMD_DONE_EN
interrupt would have been disabled and hence it will never receive one
resulting in timeout.

For chip select, in addition to setting the xfer mode to FIFO,
select_mode() to FIFO so that required interrupts are enabled.

Fixes: e5f0dfa78ac7 ("spi: spi-geni-qcom: Add support for SE DMA mode")
Suggested-by: Praveen Talari <quic_ptalari@quicinc.com
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com
Reviewed-by: Douglas Anderson <dianders@chromium.org
Link: https://lore.kernel.org/r/1683626496-9685-1-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org