pinctrl: qcom: spmi-mpp: Fix drive strength setting

[ Upstream commit 89c68b102f13f123aaef22b292526d6b92501334 ]

It looks like we parse the drive strength setting here, but never
actually write it into the hardware to update it. Parse the setting and
then write it at the end of the pinconf setting function so that it
actually sticks in the hardware.

Fixes: 0e948042 ("pinctrl: qcom: spmi-mpp: Implement support for sink mode")
Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>