spi: spi-geni-qcom: correctly handle -EPROBE_DEFER from dma_request_chan()

Now spi_geni_grab_gpi_chan() errors are correctly reported, the
-EPROBE_DEFER error should be returned from probe in case the
GPI dma driver is built as module and/or not probed yet.

Fixes: b59c1224 ("spi: spi-geni-qcom: Add support for GPI dma")
Fixes: 6532582c

 ("spi: spi-geni-qcom: fix error handling in spi_geni_grab_gpi_chan()")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230615-topic-sm8550-upstream-fix-spi-geni-qcom-probe-v2-1-670c3d9e8c9c@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>