regulator: qcom_spmi: Improve readability for setting up enable/mode pin control

By checking data->pin_ctrl_enable / data->pin_ctrl_hpm flags first, then
use switch-case to improve readability.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200801054820.134859-1-axel.lin@ingics.com


Signed-off-by: Mark Brown <broonie@kernel.org>