ARM: i.MX: edmqmx6: Copy fdt to SDRAM

barebox only recognizes boarddata as dtb if it is inside SDRAM, so
copy the dtb there if necessary.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
ARM: i.MX: edmqmx6: update defconfig

on the edmqmx6 barebox is loaded into SRAM, so it must not get
too big. Disable some stuff to make the image fit into SRAM again.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Release v2014.02.0

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>