pinctrl: qcom: Add sm8250 pinctrl driver.

Add initial Qualcomm SM8250 pinctrl driver to support pin configuration
with pinctrl framework for SM8250 SoC.

Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Signed-off-by: Venkata Narendra Kumar Gutta <vnkgutta@codeaurora.org>
Link: https://lore.kernel.org/r/1586477057-7636-2-git-send-email-vnkgutta@codeaurora.org


[bjorn: Regrouped functions, upstream tiles implementation, dropped
        downstream-only features]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200417061907.1226490-3-bjorn.andersson@linaro.org


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>