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/Makefile b/board/mikrotik/crs305-1g-4s/Makefile
new file mode 100644
index 0000000..895331b
--- /dev/null
+++ b/board/mikrotik/crs305-1g-4s/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2015 Stefan Roese <sr@denx.de>
+
+obj-y	:= crs305-1g-4s.o
+extra-y	:= kwbimage.cfg
+
+quiet_cmd_sed = SED     $@
+      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $<)$(@F)
+
+SEDFLAGS_kwbimage.cfg =-e "s|^BINARY.*|BINARY $(srctree)/$(@D)/binary.0 0000005b 00000068|"
+$(src)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
+		include/config/auto.conf
+	  $(call if_changed,sed)