lib/xlat_tables: Add support for ARMv8.4-TTST

lib/xlat_tables: Add support for ARMv8.4-TTST

ARMv8.4-TTST (Small Translation tables) relaxes the lower limit on the
size of translation tables by increasing the maximum permitted value
of the T1SZ and T0SZ fields in TCR_EL1, TCR_EL2, TCR_EL3, VTCR_EL2 and
VSTCR_EL2.

This feature is supported in AArch64 state only.

This patch adds support for this feature to both versions of the
translation tables library. It also removes the static build time
checks for virtual address space size checks to runtime assertions.

Change-Id: I4e8cebc197ec1c2092dc7d307486616786e6c093
Signed-off-by: Sathees Balya <sathees.balya@arm.com>