configs: zynq: Add config support for ZYBO

This patch adds config support needed for ZYBO target and has
been tested on Rev. B ZYBO hardware.

Signed-off-by: Tinghui Wang <steven.wang@digilentinc.com>
[PC changes:
 * Dropped boards.cfg change (rebase conflict)
 * Dropped custom u-boot env
 * Added DTS
 * Misc forward-porting changes
]
Signed-off-by: Peter Crosthwiate <crosthwaite.peter@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

include/configs/zynq_zybo.h

+/*
+ * (C) Copyright 2012 Xilinx
+ * (C) Copyright 2014 Digilent Inc.
+ *
+ * Configuration for Zynq Development Board - ZYBO
+ * See zynq-common.h for Zynq common configs
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __CONFIG_ZYNQ_ZYBO_H
+#define __CONFIG_ZYNQ_ZYBO_H
+
+#define CONFIG_SYS_SDRAM_SIZE (512 * 1024 * 1024)
+
+#define CONFIG_ZYNQ_SERIAL_UART1
+#define CONFIG_ZYNQ_GEM0
+#define CONFIG_ZYNQ_GEM_PHY_ADDR0	0
+
+#define CONFIG_SYS_NO_FLASH
+
+#define CONFIG_ZYNQ_SDHCI0
+#define CONFIG_ZYNQ_BOOT_FREEBSD
+#define CONFIG_DEFAULT_DEVICE_TREE	zynq-zybo
+
+/* Define ZYBO PS Clock Frequency to 50MHz */
+#define CONFIG_ZYNQ_PS_CLK_FREQ	50000000UL
+
+#include <configs/zynq-common.h>
+
+#endif /* __CONFIG_ZYNQ_ZYBO_H */