pci: Add Apple PCIe controller driver

This driver supports the PCIe controller on the Apple M1 and
M2 SoCs.  The code is adapted from the Linux driver.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c9a44eb..5e112e6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -965,6 +965,7 @@
 	bool "Apple SoCs"
 	select ARM64
 	select CLK
+	select CMD_PCI
 	select CMD_USB
 	select DM
 	select DM_GPIO
@@ -979,6 +980,7 @@
 	select LINUX_KERNEL_IMAGE_HEADER
 	select OF_BOARD_SETUP
 	select OF_CONTROL
+	select PCI
 	select PINCTRL
 	select POSITION_INDEPENDENT
 	select POWER_DOMAIN