SPM needs to map a number of regions on behalf of the secure partition.
Previously, it used to get a list of them from platform code using the
plat_get_secure_partition_mmap() API. Now it gets them from the resource
description structure.
The SPM<->SP shared buffer is mapped dynamically at EL3. This buffer is
used to pass information between SPM and SP, so it must be mapped at EL3
as well in order to be used by SPM.
Dynamic translation tables have been enabled when the Trusted Firmware
is compiled with SPM support.