pinctrl: pinctrl-rockchip: Fix a bunch of kerneldoc misdemeanours

pinctrl: pinctrl-rockchip: Fix a bunch of kerneldoc misdemeanours

Demote headers which are clearly not kerneldoc, provide titles for
struct definition blocks, fix API slip (bitrot) misspellings and
provide some missing entries.

Fixes the following W=1 kernel build warning(s):

 drivers/pinctrl/pinctrl-rockchip.c:82: warning: cannot understand function prototype: 'struct rockchip_iomux '
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_IO_DEFAULT' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_IO_1V8_OR_3V0' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_IO_1V8_ONLY' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_IO_1V8_3V0_AUTO' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_IO_3V3_ONLY' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:97: warning: Enum value 'DRV_TYPE_MAX' not described in enum 'rockchip_pin_drv_type'
 drivers/pinctrl/pinctrl-rockchip.c:106: warning: Enum value 'PULL_TYPE_IO_DEFAULT' not described in enum 'rockchip_pin_pull_type'
 drivers/pinctrl/pinctrl-rockchip.c:106: warning: Enum value 'PULL_TYPE_IO_1V8_ONLY' not described in enum 'rockchip_pin_pull_type'
 drivers/pinctrl/pinctrl-rockchip.c:106: warning: Enum value 'PULL_TYPE_MAX' not described in enum 'rockchip_pin_pull_type'
 drivers/pinctrl/pinctrl-rockchip.c:109: warning: Cannot understand  * @drv_type: drive strength variant using rockchip_perpin_drv_type
 on line 109 - I thought it was a doc line
 drivers/pinctrl/pinctrl-rockchip.c:122: warning: Cannot understand  * @reg_base: register base of the gpio bank
 on line 109 - I thought it was a doc line
 drivers/pinctrl/pinctrl-rockchip.c:325: warning: Function parameter or member 'route_location' not described in 'rockchip_mux_route_data'
 drivers/pinctrl/pinctrl-rockchip.c:328: warning: Cannot understand  */
 on line 109 - I thought it was a doc line
 drivers/pinctrl/pinctrl-rockchip.c:375: warning: Function parameter or member 'data' not described in 'rockchip_pin_group'
 drivers/pinctrl/pinctrl-rockchip.c:387: warning: Function parameter or member 'ngroups' not described in 'rockchip_pmx_func'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: linux-rockchip@lists.infradead.org
Link: https://lore.kernel.org/r/20200713144930.1034632-20-lee.jones@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>