arm: bcmbca: add bcm4912 SoC support

BCM4912 is a Broadcom B53 based WLAN AP router SoC. It is part of the
BCA (Broadband Carrier Access origin) chipset family so it's added under
ARCH_BCMBCA platform. This initial support includes a bare-bone
implementation and dts with CPU subsystem, memory and ARM PL011 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: Florian Fainelli <f.fainelli@gmail.com>
diff --git a/board/broadcom/bcmbca/Kconfig b/board/broadcom/bcmbca/Kconfig
index 6beb141..7bdd96b 100644
--- a/board/broadcom/bcmbca/Kconfig
+++ b/board/broadcom/bcmbca/Kconfig
@@ -16,6 +16,13 @@
 
 endif
 
+if TARGET_BCM94912
+
+config SYS_CONFIG_NAME
+	default "bcm94912"
+
+endif
+
 if TARGET_BCM963138
 
 config SYS_CONFIG_NAME