[POWERPC] Virtex: Add generic Xilinx Virtex board support

Adds support for generic Xilinx Virtex boards.  Any board which specifies
"xilinx,virtex" in the compatible property will make use of this board
support.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

arch/powerpc/platforms/40x/Makefile

 obj-$(CONFIG_WALNUT) += walnut.o
+obj-$(CONFIG_XILINX_VIRTEX_GENERIC_BOARD) += virtex.o

arch/powerpc/platforms/40x/virtex.c

+/*
+ * Xilinx Virtex (IIpro & 4FX) based board support
+ *
+ * Copyright 2007 Secret Lab Technologies Ltd.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/of_platform.h>
+#include <asm/machdep.h>
+#include <asm/prom.h>
+#include <asm/time.h>
+#include <asm/xilinx_intc.h>
+
+static int __init virtex_device_probe(void)
+{
+	if (!machine_is(virtex))
+		return 0;
+
+	of_platform_bus_probe(NULL, NULL, NULL);
+
+	return 0;
+}
+device_initcall(virtex_device_probe);
+
+static int __init virtex_probe(void)
+{
+	unsigned long root = of_get_flat_dt_root();
+
+	if (!of_flat_dt_is_compatible(root, "xilinx,virtex"))
+		return 0;
+
+	return 1;
+}
+
+static void __init virtex_setup_arch(void)
+{
+}
+
+define_machine(virtex) {
+	.name			= "Xilinx Virtex",
+	.probe			= virtex_probe,
+	.setup_arch		= virtex_setup_arch,
+	.init_IRQ		= xilinx_intc_init_tree,
+	.get_irq		= xilinx_intc_get_irq,
+	.calibrate_decr		= generic_calibrate_decr,
+};