refactor(plat/qemu): increase the non-secure DRAM size

In the qemu memory map 1GB and up is RAM. Change the
size of NS DRAM to 3GB to support VM's with more
memory requirements.
Signed-off-by: Ruchika Gupta <ruchika.gupta@linaro.org>
Change-Id: If15cf3b9d3e2e7876c40ce888f22e887893fe696

plat/qemu/qemu/include/platform_def.h

@@ -81,7 +81,7 @@
 #define SEC_ROM_SIZE			0x00020000
 
 #define NS_DRAM0_BASE			0x40000000
-#define NS_DRAM0_SIZE			0x3de00000
+#define NS_DRAM0_SIZE			0xc0000000
 
 #define SEC_SRAM_BASE			0x0e000000
 #define SEC_SRAM_SIZE			0x00060000