hikey960: Increase max xlat tables
hikey960: Increase max xlat tables

It is cleaner to use the same number of tables regardless of whether
OP-TEE is used or not. This doesn't result in a significant memory
usage increase.

Change-Id: I38bcaa3f2f197c0a352153117592749f189a265c
Signed-off-by: Joel Hutton <dd4a22c4cf7172da81944b53f2d07b1b34bde0cc@Arm.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware