pinctrl: mediatek: mt7622: add antsel pins/groups

These pins are named ANTSEL[0~29] in datasheet and are used by wmac for
various functions.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200922164159.120920-1-gch981213@gmail.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>