arm64: add config for Broadcom BCM4908 SoCs

Add ARCH_BCM4908 config that can be used for compiling DTS files.
Signed-off-by: NRafał Miłecki <rafal@milecki.pl>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>

arch/arm64/Kconfig.platforms

@@ -43,6 +43,14 @@ config ARCH_BCM2835
 	  This enables support for the Broadcom BCM2837 and BCM2711 SoC.
 	  These SoCs are used in the Raspberry Pi 3 and 4 devices.
 
+config ARCH_BCM4908
+	bool "Broadcom BCM4908 family"
+	select GPIOLIB
+	help
+	  This enables support for the Broadcom BCM4906, BCM4908 and
+	  BCM49408 SoCs. These SoCs use Brahma-B53 cores and can be
+	  found in home routers.
+
 config ARCH_BCM_IPROC
 	bool "Broadcom iProc SoC Family"
 	select COMMON_CLK_IPROC

arch/arm64/configs/defconfig

@@ -32,6 +32,7 @@ CONFIG_ARCH_AGILEX=y
 CONFIG_ARCH_SUNXI=y
 CONFIG_ARCH_ALPINE=y
 CONFIG_ARCH_BCM2835=y
+CONFIG_ARCH_BCM4908=y
 CONFIG_ARCH_BCM_IPROC=y
 CONFIG_ARCH_BERLIN=y
 CONFIG_ARCH_BRCMSTB=y