board: ns2: Add support for Broadcom Northstar 2

Add support for the Broadcom Northstar2 SoC and SVK (bcm958712k).  The
BCM5871X is a series of quad-core 64-bit 2GHz ARMv8 Cortex-A57
processors targeting a broad range of networking applications.

Signed-off-by: Jon Mason <jon.mason@broadcom.com>
diff --git a/configs/bcm958712k_defconfig b/configs/bcm958712k_defconfig
new file mode 100644
index 0000000..96e4bce
--- /dev/null
+++ b/configs/bcm958712k_defconfig
@@ -0,0 +1,10 @@
+CONFIG_ARM=y
+CONFIG_TARGET_BCMNS2=y
+CONFIG_IDENT_STRING=" Broadcom Northstar 2"
+CONFIG_DISTRO_DEFAULTS=y
+CONFIG_BOOTDELAY=5
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_SYS_PROMPT="u-boot> "
+# CONFIG_CMD_IMLS is not set
+CONFIG_SYS_NS16550=y
+CONFIG_OF_LIBFDT=y