MAINTAINERS: Update freescale pin controllers maintainer

Add myself as co-maintainer of freescale pin controllers driver.
As Stefan is no longer working on NXP pin controller, so remove
Stefan from the list as suggested by him.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/r/20220711083528.27710-1-ping.bai@nxp.com


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