doc: zynq: Add information on zynq u-boot

Information on zynq u-boot about
- zynq boards
- mainline status
- TODO

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>

doc/README.zynq

+#
+# Xilinx ZYNQ U-Boot
+#
+# (C) Copyright 2013 Xilinx, Inc.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+1. About this
+
+This document describes the information about Xilinx Zynq U-Boot -
+like supported boards, ML status and TODO list.
+
+2. Zynq boards
+
+Xilinx Zynq-7000 All Programmable SoCs enable extensive system level
+differentiation, integration, and flexibility through hardware, software,
+and I/O programmability.
+
+* zc70x
+  - zc702 (single qspi, gem0, mmc) [1]
+  - zc706 (dual parallel qspi, gem0, mmc) [2]
+* zed (single qspi, gem0, mmc) [3]
+* microzed (single qspi, gem0, mmc) [4]
+* zc770
+  - zc770-xm010 (single qspi, gem0, mmc)
+  - zc770-xm011 (8 or 16 bit nand)
+  - zc770-xm012 (nor)
+  - zc770-xm013 (dual parallel qspi, gem1)
+
+3. Mainline status
+
+- Added basic board configurations support.
+- Added zynq u-boot bsp code - arch/arm/cpu/armv7/zynq
+- Added zynq boards named - zynq, zynq_dcc
+- Added zynq drivers:
+  serial - drivers/serial/serial_zynq.c
+  net - drivers/net/zynq_gem.c
+  mmc - drivers/mmc/zynq_sdhci.c
+  mmc - drivers/mmc/zynq_sdhci.c
+  spi-  drivers/spi/zynq_spi.c
+  i2c - drivers/i2c/zynq_i2c.c
+
+4. TODO
+
+- Add zynq boards support - zc70x, zed, microzed, zc770
+- Add zynq qspi controller driver
+- Add zynq nand controller driver
+- d-cache support for zynq_gem.c
+- FDT support for zynq boards
+- Need proper cleanups on board configurations
+
+[1] http://www.xilinx.com/products/boards-and-kits/EK-Z7-ZC702-G.htm
+[2] http://www.xilinx.com/products/boards-and-kits/EK-Z7-ZC706-G.htm
+[3] http://zedboard.org/product/zedboard
+[4] http://zedboard.org/product/microzed
+
+--
+Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
+Sun Dec 15 14:52:41 IST 2013