pinctrl: ralink: rename variables which point out the pin group

These variables define a list of functions which can be muxed to the pin
group which the name of the pin group was originally intended to be pointed
out on the name of the said variables.

Therefore, rename "func" to "grp" across all subdrivers where this applies.

Fixes: 18653d4b ("pinctrl: ralink: rename variable names for functions on MT7620 and MT7621")
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20221231160849.40544-2-arinc.unal@arinc9.com


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