Add support for the Calao SBC35-A9G20 board

The Calao SBC35-A9G20 board is manufactured and sold by Calao Systems
<http://www.calao-systems.com>. It is built around an AT91SAM9G20 ARM SoC
running at 400MHz. It features an Ethernet port, an SPI RTC backed by an onboard
battery , an SD/MMC slot, a CompactFlash slot, 64Mo of SDRAM, 256Mo of NAND
flash, two USB host ports, and an USB device port. More informations can be
found at <http://www.calao-systems.com/articles.php?lng=en&pg=5936>

Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
diff --git a/Makefile b/Makefile
index bffc036..ee464eb 100644
--- a/Makefile
+++ b/Makefile
@@ -2897,6 +2897,13 @@
 pm9263_config	:	unconfig
 	@$(MKCONFIG) $(@:_config=) arm arm926ejs pm9263 ronetix at91
 
+SBC35_A9G20_NANDFLASH_config \
+SBC35_A9G20_EEPROM_config \
+SBC35_A9G20_config	:	unconfig
+	@mkdir -p $(obj)include
+	@echo "#define CONFIG_$(@:_config=) 1" >$(obj)include/config.h
+	@$(MKCONFIG) -a sbc35_a9g20 arm arm926ejs sbc35_a9g20 calao at91
+
 ########################################################################
 ## ARM Integrator boards - see doc/README-integrator for more info.
 integratorap_config	\