This patch removes support for legacy Versatile Express memory map for the
GIC peripheral in the FVP platform. The user guide is also updated for the
same.

Change-Id: Ib8cfb819083aca359e5b46b5757cb56cb0ea6533

This patch modifies the upstream platform port makefiles to use the new
xlat_tables library files. This patch also makes mmap region setup common
between AArch64 and AArch32 for FVP platform port. The file `fvp_common.c`
is moved from the `plat/arm/board/fvp/aarch64` folder to the parent folder
as it is not specific to AArch64.

Change-Id: Id2e9aac45e46227b6f83cccfd1e915404018ea0b