arm: bcmbca: add bcm63148 SoC support

BCM63148 is an Broadcom B15 based DSL Broadband 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 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.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
diff --git a/include/configs/bcm963148.h b/include/configs/bcm963148.h
new file mode 100644
index 0000000..5a24ccc
--- /dev/null
+++ b/include/configs/bcm963148.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2022 Broadcom Ltd.
+ */
+
+#ifndef __BCM963148_H
+#define __BCM963148_H
+
+#define CONFIG_SYS_SDRAM_BASE		0x00000000
+
+#endif