Enable ARM_XLAT_TABLES_LIB_V1 as ZynqMP is using
v1 library of translation tables.

With upstream patch d323af9,
the usage of MAP_REGION_FLAT is referring to definition in file
include/lib/xlat_tables/xlat_tables_v2.h but while preparing
xlat tables in lib/xlat_tables/xlat_tables_common.c it is referring
to include/lib/xlat_tables/xlat_tables.h which is v1 xlat tables.
Also, ZynqMP was using v1 so defined ARM_XLAT_TABLES_LIB_V1 to
use v1 xlat tables everywhere.
This fixes the issue of xlat tables failures as it takes v2
library mmap_region structure in some files and v1 in other
files.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>