sh: pfc: Rudimentary pinctrl-backed GPIO support.

This begins the migration of the PFC core to the pinctrl subsystem.
Initial support is very basic, with the bulk of the implementation simply
being nopped out in such a way to allow registration with the pinctrl
core to succeed.

The gpio chip driver is stripped down considerably now relying purely on
pinctrl API calls to manage the bulk of its operations.

This provides a basis for further PFC refactoring, including decoupling
pin functions from the GPIO API, establishing pin groups, and so forth.
These will all be dealt with incrementally so as to introduce as few
growing and migratory pains to tree-wide PFC pinmux users today.

When the interfaces have been well established and in-tree users have
been migrated off of the legacy interfaces it will be possible to strip
down the core considerably, leading to eventual drivers/pinctrl rehoming.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/linux/sh_pfc.h

@@ -132,6 +132,9 @@ struct sh_pfc {
 /* drivers/sh/pfc/gpio.c */
 int sh_pfc_register_gpiochip(struct sh_pfc *pfc);
 
+/* drivers/sh/pfc/pinctrl.c */
+int sh_pfc_register_pinctrl(struct sh_pfc *pfc);
+
 /* drivers/sh/pfc/core.c */
 int register_sh_pfc(struct sh_pfc *pfc);
 
@@ -144,8 +147,6 @@ int sh_pfc_gpio_to_enum(struct sh_pfc *pfc, unsigned gpio, int pos,
 			pinmux_enum_t *enum_idp);
 int sh_pfc_config_gpio(struct sh_pfc *pfc, unsigned gpio, int pinmux_type,
 		       int cfg_mode);
-int sh_pfc_set_direction(struct sh_pfc *pfc, unsigned gpio,
-			 int new_pinmux_type);
 
 /* xxx */
 static inline int register_pinmux(struct pinmux_info *pip)