arm: bcmbca: add bcm6856 SoC support under CONFIG_ARCH_BCMBCA

BCM6856 is a Broadcom B53 based PON Gateway SoC. It is part of the BCA
(Broadband Carrier Access origin) chipset family. Like other Broadband
SoC, this patch adds it under CONFIG_BCM6856 chip config and
CONFIG_ARCH_BCMBCA platform config.

This initial support includes a bare-bone implementation and dts with
CPU subsystem, memory and Broadcom uart. This SoC is supported in the
linux-next git repository so the dts and dtsi files are copied from
linux.

The u-boot image can be loaded from flash or network to the entry point
address in the memory and boot from there to the console.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/arch/arm/mach-bcmbca/Kconfig b/arch/arm/mach-bcmbca/Kconfig
index d786188..f35f02c 100644
--- a/arch/arm/mach-bcmbca/Kconfig
+++ b/arch/arm/mach-bcmbca/Kconfig
@@ -83,6 +83,16 @@
 	select DM_SERIAL
 	select BCM6345_SERIAL
 
+config BCM6856
+	bool "Support for Broadcom 6856 Family"
+	select ARM64
+	select SYS_ARCH_TIMER
+	select DM_SERIAL
+	select BCM6345_SERIAL
+	help
+	  Broadcom BCM6856 is a dual core Brahma-B53 ARMv8 based xPON Gateway
+	  SoC. This SoC family includes BCM6856, BCM6836 and BCM4910.
+
 config BCM6878
 	bool "Support for Broadcom 6878 Family"
 	select SYS_ARCH_TIMER
@@ -101,6 +111,7 @@
 source "arch/arm/mach-bcmbca/bcm6756/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6813/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6846/Kconfig"
+source "arch/arm/mach-bcmbca/bcm6856/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6878/Kconfig"
 
 endif