pinctrl: imx8mq: Don't depend on SOC_IMX8MQ

SOC_IMX8MQ does not exist. Use `ARCH_MXC && ARM64` as CLK_IMX8MQ does.
This seems to be a leftover from the SOC_IMX8MQ <-> ARCH_MXC rework.
Signed-off-by: Guido Günther <agx@sigxcpu.org>

drivers/pinctrl/freescale/Kconfig

@@ -123,7 +123,7 @@ config PINCTRL_IMX7ULP
 
 config PINCTRL_IMX8MQ
 	bool "IMX8MQ pinctrl driver"
-	depends on SOC_IMX8MQ
+	depends on ARCH_MXC && ARM64
 	select PINCTRL_IMX
 	help
 	  Say Y here to enable the imx8mq pinctrl driver