This patch allows to use DDR address in memory node because on FPGA we
typically use DDR instead of shared RAM.

This patch also modifies the kernel arguments to allow the rootfs to be
mounted from a direct mapping of the QSPI NOR flash using the physmap
driver in the kernel. This allows to support CRAMFS XIP.

Change-Id: I4e2bc6a1f48449c7f60e00f5f1a698df8cb2ba89
Signed-off-by: Vishnu Banavath <vishnu.banavath@arm.com>
Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>