pinctrl: qcom: spmi-gpio: Fix pmic_gpio_config_get() to be compliant

pinctrl: qcom: spmi-gpio: Fix pmic_gpio_config_get() to be compliant

If you do this on an sdm845 board:
  grep "" /sys/kernel/debug/pinctrl/*spmi:pmic*/pinconf-groups

...it looks like nonsense.  For every pin you see listed:
  input bias disabled, input bias high impedance, input bias pull down, input bias pull up, ...

That's because pmic_gpio_config_get() isn't complying with the rules
that pinconf_generic_dump_one() expects.  Specifically for boolean
parameters (anything with a "struct pin_config_item" where has_arg is
false) the function expects that the function should return its value
not through the "config" parameter but should return "0" if the value
is set and "-EINVAL" if the value isn't set.

Let's fix this.

From a quick sample of other pinctrl drivers, it appears to be
tradition to also return 1 through the config parameter for these
boolean parameters when they exist.  I'm not one to knock tradition,
so I'll follow tradition and return 1 in these cases.  While I'm at
it, I'll also continue searching for four leaf clovers, kocking on
wood three times, and trying not to break mirrors.

NOTE: This also fixes an apparent typo for reading
PIN_CONFIG_BIAS_DISABLE where the old driver was accidentally
using "=" instead of "==" and thus was setting some internal
state when you tried to query PIN_CONFIG_BIAS_DISABLE.  Oops.

Fixes: eadff3024472 ("pinctrl: Qualcomm SPMI PMIC GPIO pin controller driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>