armv8/ls2085a: Expose all DDR region(s) to Linux

This patch allows u-boot to expose the complete DDR region(s) to Linux
(after subtracting the memory hidden via MEM_TOP_HIDE mechanism).

This allows the u-boot to support the 48-bit VA support provided by
ARM64 Linux in flavors 3.18 and above, by passing the appropriate
'memory' DTS nodes.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma at freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar at freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/ls2085ardb/README b/board/freescale/ls2085ardb/README
index cfd5185..2f18243 100644
--- a/board/freescale/ls2085ardb/README
+++ b/board/freescale/ls2085ardb/README
@@ -107,3 +107,14 @@
 ---------------
 a) NOR boot
 b) NAND boot
+
+Booting Linux flavors which do not support 48-bit VA (< Linux 3.18)
+-------------------------------------------------------------------
+One needs to use appropriate bootargs to boot Linux flavors which do
+not support 48-bit VA (for e.g. < Linux 3.18) by appending mem=2048M, as shown
+below:
+
+=> setenv bootargs 'console=ttyS1,115200 root=/dev/ram
+   earlycon=uart8250,mmio,0x21c0600,115200 default_hugepagesz=2m hugepagesz=2m
+   hugepages=16 mem=2048M'
+