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/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 8b97143..56bf5aa 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -162,7 +162,8 @@
 	armada-38x-controlcenterdc.dtb		\
 	armada-385-atl-x530.dtb			\
 	armada-385-atl-x530DP.dtb		\
-	armada-xp-db-xc3-24g4xg.dtb
+	armada-xp-db-xc3-24g4xg.dtb		\
+	armada-xp-crs305-1g-4s.dtb
 
 dtb-$(CONFIG_ARCH_UNIPHIER_LD11) += \
 	uniphier-ld11-global.dtb \