ARM: zynq: dts: split up device tree

The purpose of the created zynq-7000.dtsi file is to describe the
hardware common to all Zynq 7000-based boards.  Also, get rid of the
zynq-ep107 device tree, since it is not hardware anyone can purchase.

Add a zc702 dts file based on the zynq-7000.dtsi.  Add it to the
dts/Makefile so it is built with the 'dtbs' target.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
index f37cf9f..76ed11e 100644
--- a/arch/arm/boot/dts/Makefile
+++ b/arch/arm/boot/dts/Makefile
@@ -103,5 +103,6 @@
 dtb-$(CONFIG_ARCH_VT8500) += vt8500-bv07.dtb \
 	wm8505-ref.dtb \
 	wm8650-mid.dtb
+dtb-$(CONFIG_ARCH_ZYNQ) += zynq-zc702.dtb
 
 endif