spi: spi-geni-qcom: Simplify probe function

Re-arrange existing APIs in probe function to
avoid using goto and remove redundant variables.

Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>