pinctrl: qcom: spmi-gpio: add support to enable/disable output

pinctrl: qcom: spmi-gpio: add support to enable/disable output

Currently, if the GPIO is configured as output in the bootloader
and user changes the mode to input in HLOS, it would end up
getting configured as input/output. Functionally, this is fine;
however, there may be some requirements where the output needs
to be disabled so that it can be used only for input.

Add support to enable/disable output mode through "output-enable"
or "output-disable" pinctrl properties.

Signed-off-by: Subbaraman Narayanamurthy <quic_subbaram@quicinc.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1631588246-4811-3-git-send-email-quic_subbaram@quicinc.com
[Drop copyright change which is already upstrean in -rcN]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>