ARM: dts: imx: Add basic dts support for imx6qp SOC

The i.MX6Quad Plus processor is an high performance SOC of i.MX6 family.
It has enhanced graphics performance and increased overall memory bandwidth
compared to i.MX6Q. Most of the design are same as i.MX6Quad/Dual, so code
for i.MX6Quad can be resued by this chip. The revision number is identied as
i.MX6Q Rev2.0, but actually it is a new chip, as we did many change to the
overall architecture.

This patch adds basic dtsi file support for the new i.MX6Quad Plus processor.

Signed-off-by: Bai Ping <ping.bai@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>