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/board/calao/sbc35_a9g20/config.mk b/board/calao/sbc35_a9g20/config.mk
new file mode 100644
index 0000000..ff2cfd1
--- /dev/null
+++ b/board/calao/sbc35_a9g20/config.mk
@@ -0,0 +1 @@
+TEXT_BASE = 0x23f00000