pinctrl: imx8qxp: break the dependency on SOC_IMX8QXP

ARM64 SoC does not encourage people to add more finegrained SoC
config options rather than a single ARCH_<family> in arch Kconfig.
So this patch aims to break the dependency on SOC_IMX8QXP.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>