pinctrl: cherryview: Describe members of couple of structs

Compiler unsatisfied to see half described data structures
and issues warnings:

drivers/pinctrl/intel/pinctrl-cherryview.c:136: warning: Function parameter or member 'acpi_space_id' not described in 'chv_community'
drivers/pinctrl/intel/pinctrl-cherryview.c:169: warning: Function parameter or member 'saved_intmask' not described in 'chv_pinctrl'
drivers/pinctrl/intel/pinctrl-cherryview.c:169: warning: Function parameter or member 'saved_pin_context' not described in 'chv_pinctrl'

To satisfy it, describe mentioned members.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>