ramips: replace pinctrl property names

ramips: replace pinctrl property names

Upstream pinctrl driver in drivers/staging uses
groups/function/ralink,num-gpios instead of
ralink,group/ralink,function/ralink,nr-gpio
Replace these properties in dts as well as the pinctrl driver in
patches-4.14.
This commit is created using:
sed -i 's/ralink,group/groups/g'
sed -i 's/ralink,function/function/g'
sed -i 's/ralink,nr-gpio/ralink,num-gpios/g'

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>