pinctrl: sh-pfc: Do not unconditionally support PIN_CONFIG_BIAS_DISABLE

pinctrl: sh-pfc: Do not unconditionally support PIN_CONFIG_BIAS_DISABLE

Always stating PIN_CONFIG_BIAS_DISABLE is supported gives untrue output
when examining /sys/kernel/debug/pinctrl/e6060000.pfc/pinconf-pins if
the operation get_bias() is implemented but the pin is not handled by
the get_bias() implementation. In that case the output will state that
"input bias disabled" indicating that this pin has bias control
support.

Make support for PIN_CONFIG_BIAS_DISABLE depend on that the pin either
supports SH_PFC_PIN_CFG_PULL_UP or SH_PFC_PIN_CFG_PULL_DOWN. This also
solves the issue where SoC specific implementations print error messages
if their particular implementation of {set,get}_bias() is called with a
pin it does not know about.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>