[PATCH v2 1/9] ARM: introduce ARCH_MICROCHIP for ARM64 Microchip SoCs

Add the ARCH_MICROCHIP top-level symbol so subsequent peripheral
driver patches (atmel serial, atmel-quadspi, ...) can gain
ARCH_MICROCHIP as a build dependency.

This SoC architecture covers Microchip's ARM64 switch SoCs, starting
with the LAN969X family. ARM32 Microchip/Atmel SoCs (AT91, SAMA5)
continue to use ARCH_AT91.

Assisted-by: Claude-Code:claude-opus-5
Signed-off-by: Oleksij Rempel <[email protected]>
---
Link to v1: https://lore.barebox.org/barebox/[email protected]/

Changes v2:
- also select COMMON_CLK: the SoC clock controller driver added later
  in this series depends on it
---
 arch/arm/Kconfig | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fe4fd3f47178..aed6084bef07 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -272,6 +272,21 @@ config ARCH_ZYNQMP
 	select GPIOLIB
 	select HAS_MACB
 
+config ARCH_MICROCHIP
+	bool "Microchip ARM64 SoC support"
+	depends on ARCH_MULTIARCH
+	depends on 64BIT
+	select OFDEVICE
+	select COMMON_CLK
+	select COMMON_CLK_OF_PROVIDER
+	select PINCTRL
+	select GPIOLIB
+	help
+	  This enables support for Microchip ARM64-based SoCs,
+	  including the LAN969X Ethernet switch family.
+
+	  For ARM32 Microchip/Atmel SoCs (AT91, SAMA5), use ARCH_AT91.
+
 source "arch/arm/cpu/Kconfig"
 source "arch/arm/mach-at91/Kconfig"
 source "arch/arm/mach-bcm283x/Kconfig"
-- 
2.47.3