pinctrl: Add Apple pinctrl driver

This driver supports both pin muxing and GPIO support for the
pin control logic found on Apple SoCs.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index f7f0383..eed27af 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -927,6 +927,7 @@
 	select CLK
 	select CMD_USB
 	select DM
+	select DM_GPIO
 	select DM_KEYBOARD
 	select DM_SERIAL
 	select DM_USB
@@ -935,6 +936,7 @@
 	select LINUX_KERNEL_IMAGE_HEADER
 	select OF_CONTROL
 	select OF_BOARD
+	select PINCTRL
 	select POSITION_INDEPENDENT
 	select USB
 	imply CMD_DM