pinctrl: ssbi-gpio: Fix pm8xxx_pin_config_get() to be compliant

If you look at "pinconf-groups" in debugfs for ssbi-gpio you'll notice
it looks like nonsense.

The problem is fairly well described in commit 1cf86bc2 ("pinctrl:
qcom: spmi-gpio: Fix pmic_gpio_config_get() to be compliant") and
commit 05e0c828 ("pinctrl: msm: Fix msm_config_group_get() to be
compliant"), but it was pointed out that ssbi-gpio has the same
problem.  Let's fix it there too.

Fixes: b4c45fe9 ("pinctrl: qcom: ssbi: Family A gpio & mpp drivers")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>