Reserve some DDR DRAM for secure use on FVP platforms

TZC-400 is configured to set the last 16MB of DRAM1 as secure memory and
the rest of DRAM as non-secure. Non-secure software must not attempt to
access the 16MB secure area.

Device tree files (sources and binaries) have been updated to match this
configuration, removing that memory from the Linux physical memory map.

To use UEFI and Linux with this patch, the latest version of UEFI and
the updated device tree files are required. Check the user guide in the
documentation for more details.

Replaced magic numbers with #define for memory region definition in the
platform security initialization function.

Fixes ARM-software/tf-issues#149

Change-Id: Ia5d070244aae6c5288ea0e6c8e89d92859522bfe
diff --git a/fdts/fvp-foundation-gicv3-psci.dts b/fdts/fvp-foundation-gicv3-psci.dts
index f9f1ff3..7692c61 100644
--- a/fdts/fvp-foundation-gicv3-psci.dts
+++ b/fdts/fvp-foundation-gicv3-psci.dts
@@ -91,7 +91,7 @@
 
 	memory@80000000 {
 		device_type = "memory";
-		reg = <0x00000000 0x80000000 0 0x80000000>,
+		reg = <0x00000000 0x80000000 0 0x7F000000>,
 		      <0x00000008 0x80000000 0 0x80000000>;
 	};