arm64: defconfig: Select CONFIG_PINCTRL_IMX8MP by default

Enable CONFIG_PINCTRL_IMX8MP by default to support i.MX8MP
pinctrl driver.
Signed-off-by: NAnson Huang <Anson.Huang@nxp.com>
Reviewed-by: NAbel Vesa <abel.vesa@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm64/configs/defconfig

@@ -409,6 +409,7 @@ CONFIG_PINCTRL_S700=y
 CONFIG_PINCTRL_S900=y
 CONFIG_PINCTRL_IMX8MM=y
 CONFIG_PINCTRL_IMX8MN=y
+CONFIG_PINCTRL_IMX8MP=y
 CONFIG_PINCTRL_IMX8MQ=y
 CONFIG_PINCTRL_IMX8QXP=y
 CONFIG_PINCTRL_IPQ8074=y