pinctrl: pinctrl-bm1880: Rename ill documented struct attribute entries

pinctrl: pinctrl-bm1880: Rename ill documented struct attribute entries

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

 drivers/pinctrl/pinctrl-bm1880.c:40: warning: Function parameter or member 'pctrldev' not described in 'bm1880_pinctrl'
 drivers/pinctrl/pinctrl-bm1880.c:40: warning: Function parameter or member 'pinconf' not described in 'bm1880_pinctrl'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200713144930.1034632-19-lee.jones@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>