feat(imx8/imx8m): switch to xlat_tables_v2

spd trusty requires memory dynamic mapping feature to be
enabled, so we have to use xlat table library v2 instead
of v1.

Signed-off-by: Ji Luo <ji.luo@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: I2813af9c7878b1fc2a59e27619c5b643af6a1e91