uboot-imx

imx: ventana: add support for GW5909

The GW5909 is a small single board computer based on the i.MX6DL SoC
with the same peripheral set as the GW5904 but with half the DRAM loaded
and an additional RS232 transceiver off UART2.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>