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>

Author: JackyBai

MAINTAINERS

@@ -15849,7 +15849,7 @@ PIN CONTROLLER - FREESCALE
 M:	Dong Aisheng <aisheng.dong@nxp.com>
 M:	Fabio Estevam <festevam@gmail.com>
 M:	Shawn Guo <shawnguo@kernel.org>
-M:	Stefan Agner <stefan@agner.ch>
+M:	Jacky Bai <ping.bai@nxp.com>
 R:	Pengutronix Kernel Team <kernel@pengutronix.de>
 L:	linux-gpio@vger.kernel.org
 S:	Maintained