wandboard: Switch to SPL support

Currently we need to build one U-boot image for each of the wandboard
variants: quad, dual-lite and solo.

By switching to SPL we can support all these variants with a single binary,
which is very convenient.

Based on the work from Richard Hu.

Tested kernel booting on the three boards.

Signed-off-by: Richard Hu <hakahu@gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Vagrant Cascadian <vagrant@aikidev.net>
Reviewed-by: Stefano Babic <sbabic@denx.de>
diff --git a/configs/wandboard_defconfig b/configs/wandboard_defconfig
new file mode 100644
index 0000000..1ccac5a
--- /dev/null
+++ b/configs/wandboard_defconfig
@@ -0,0 +1,6 @@
+CONFIG_SPL=y
+CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/imx-common/spl_sd.cfg,MX6QDL"
+CONFIG_ARM=y
+CONFIG_TARGET_WANDBOARD=y
+CONFIG_DM=y
+CONFIG_DM_THERMAL=y