This patch introduces the `SPCI_ID_GET` interface which will return the
ID of the calling SPCI component. Returns 0 for requests from the
non-secure world and the SPCI component ID as specified in the manifest
for secure world requests.

Change-Id: Icf81eb1d0e1d7d5c521571e04972b6e2d356e0d1
Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>
Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>

This patch adds a rudimentary SPM dispatcher component in EL3.
It does the following:

- Consumes the TOS_FW_CONFIG to determine properties of the SPM core
  component
- Initialises the SPM core component which resides in the BL32 image
- Implements a handler for SPCI calls from either security state. Some
  basic validation is done for each call but in most cases it is simply
  forwarded as-is to the "other" security state.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Change-Id: I7d116814557f7255f4f4ebb797d1619d4fbab590