fix: TF-A build options for 4 worlds

Per TF-A v2.11 CTX_INCLUDE_MTE_REGS is renamed ENABLE_FEAT_MTE2.
Now Hafnium supports SME state save/restore, enable SME for the
secure world (aka disable SME EL3 traps).

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>