zynq: import zynq-7000.dtsi from Linux Kernel

zynq: import zynq-7000.dtsi from Linux Kernel

Our current motivation is to use OF initialization for RAM and UART.
But adding full DTS would be helpful in future, for instance,
for OF configuration of Ethernet, MMC, USB, etc.

This commit imports arch/arm/boot/dts/zynq-7000.dtsi from Linux 3.15-rc5
and adjusts the license comment block for SPDX.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Suggested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>