refactor(smccc): refactor vendor-el3 build

Currently we are building vendor-specific EL3 by default similar to
arm-sip but unfortunately this causes few troubles for now.

- Few model builds configuration like 'fvp-dynamiq-aarch64-only'
  is on 256KB SRAM border and this configuration is also run on some
  older models like A710 and N2, so we cant move them to 384KB SRAM size
  and to new model.

- Not able to move some older model builds to new model due to known
  issue in power modelling in some of the models, making it difficult to
  transition.

However vendor-specific EL3 is currently using PMF, DEBUGFS so building
the vendor EL3 support only when any of this sub-service is built also
helps to avoid bloating BL31 image size in certain configurations.

However this is not end of road, we will monitor how vendor-specific EL3
grows with sub-service and if needed will make this interface to built
by default like arm-sip range. Also this doesn't stop platform owners to
make vendor-specific EL3 to be enabled by default for their platform
configuration.

Change-Id: I23322574bdeb7179441a580ad4f093216a948bbf
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
2 files changed