pinctrl: pinctrl-single: Fix struct/function documentation blocks

pinctrl: pinctrl-single: Fix struct/function documentation blocks

Add some missing attributes/parameter descriptions, remove other
superfluous ones, add struct header titles and fix misspellings.

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

 drivers/pinctrl/pinctrl-single.c:50: warning: Function parameter or member 'mask' not described in 'pcs_func_vals'
 drivers/pinctrl/pinctrl-single.c:97: warning: Function parameter or member 'conf' not described in 'pcs_function'
 drivers/pinctrl/pinctrl-single.c:97: warning: Function parameter or member 'nconfs' not described in 'pcs_function'
 drivers/pinctrl/pinctrl-single.c:659: warning: Function parameter or member 'pin_pos' not described in 'pcs_add_pin'
 drivers/pinctrl/pinctrl-single.c:985: warning: Excess function parameter 'pctldev' description in 'pcs_parse_one_pinctrl_entry'
 drivers/pinctrl/pinctrl-single.c:1357: warning: Cannot understand  * @reg:        virtual address of interrupt register
 drivers/pinctrl/pinctrl-single.c:1377: warning: Function parameter or member 'pcs_soc' not described in 'pcs_irq_set'
 drivers/pinctrl/pinctrl-single.c:1377: warning: Function parameter or member 'irq' not described in 'pcs_irq_set'
 drivers/pinctrl/pinctrl-single.c:1377: warning: Function parameter or member 'enable' not described in 'pcs_irq_set'
 drivers/pinctrl/pinctrl-single.c:1458: warning: Function parameter or member 'pcs_soc' not described in 'pcs_irq_handle'
 drivers/pinctrl/pinctrl-single.c:1458: warning: Excess function parameter 'pcs_irq' description in 'pcs_irq_handle'
 drivers/pinctrl/pinctrl-single.c:1506: warning: Excess function parameter 'irq' description in 'pcs_irq_chain_handler'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: linux-omap@vger.kernel.org
Link: https://lore.kernel.org/r/20200713144930.1034632-22-lee.jones@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>