ARM: dts: imx: add support for TX6QP

The TX6QP-8037 is a Computer On Module manufactured by
  Ka-Ro electronics GmbH with the following characteristics:
  Processor    Freescale i.MX 6QuadPlus MCIMX6QP7, 1 GHz
  RAM          1GiB 64-bit DDR3 SDRAM
  ROM          4GB HiRel eMMC
  Power supply Single 3.3 to 5V
  Size         26mm SO-DIMM
  Temp. Range  -40°C to 105°C

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>