pinctrl: thunderbay: Drop empty platform remove function

A remove callback just returning 0 is equivalent to no remove callback
at all. So drop the useless function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20221213182322.962345-1-u.kleine-koenig@pengutronix.de


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