arm: mvebu: Add CRS305-1G-4S board

CRS305-1G-4S has a switch chip with an integrated CPU (98DX3236) and
like some of the other similar boards requires bin_hdr.
bin_hdr (DDR3 init stage) is currently retrieved from the stock
bootloader and compiled into the kwb image.

Adds support for U-Boot, enable UART, SPI, Winbond SPI flash chip
support and writing env to SPI flash.

Signed-off-by: Luka Kovacic <me@lukakovacic.xyz>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/mikrotik/crs305-1g-4s/kwbimage.cfg.in b/board/mikrotik/crs305-1g-4s/kwbimage.cfg.in
new file mode 100644
index 0000000..2dbbbd0
--- /dev/null
+++ b/board/mikrotik/crs305-1g-4s/kwbimage.cfg.in
@@ -0,0 +1,12 @@
+#
+# Copyright (C) 2014 Stefan Roese <sr@denx.de>
+#
+
+# Armada XP uses version 1 image format
+VERSION		1
+
+# Boot Media configurations
+BOOT_FROM	spi
+
+# Binary Header (bin_hdr) with DDR3 training code
+BINARY board/mikrotik/crs305-1g-4s/binary.0 0000005b 00000068