ARM: vexpress: Add Device Tree support

This patch adds generic Versatile Express DT machine description,
Device Tree description for the motherboard and documentation for
the bindings.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>

arch/arm/mach-vexpress/include/mach/motherboard.h

@@ -116,6 +116,12 @@ int v2m_cfg_write(u32 devfn, u32 data);
 int v2m_cfg_read(u32 devfn, u32 *data);
 void v2m_flags_set(u32 data);
 
+/*
+ * Miscellaneous
+ */
+#define SYS_MISC_MASTERSITE	(1 << 14)
+#define SYS_PROCIDx_HBI_MASK	0xfff
+
 /*
  * Core tile IDs
  */