feat(spmc): add support for FF-A power mgmt. messages in the EL3 SPMC

This patch adds support for forwarding the following PSCI messages
received by the SPMC at EL3 to the S-EL1 SP if the SP has indicated
that it wishes to receive the appropriate message via its manifest.

1. A PSCI CPU_OFF message in response to a cpu hot unplug request
   from the OS.
2. A message to indicate warm boot of a cpu in response to a cpu
   hot plug request from the OS.
3. A PSCI CPU_SUSPEND message in response to a cpu idle event
   initiated from the OS.
4. A message to indicate warm boot of a cpu from a shallow power
   state in response to a cpu resume power event.

This patch also implements the FFA_SECONDARY_EP_REGISTER function to
enable the SP specify its secondary entrypoint.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: I375d0655b2c6fc27445facc39213d1d0678557f4
diff --git a/services/std_svc/spmd/spmd_main.c b/services/std_svc/spmd/spmd_main.c
index 777a962..745c949 100644
--- a/services/std_svc/spmd/spmd_main.c
+++ b/services/std_svc/spmd/spmd_main.c
@@ -684,7 +684,7 @@
 			    (SMC_GET_GP(gpregs, CTX_GPREG_X0) !=
 				FFA_MSG_SEND_DIRECT_RESP_SMC32) ||
 			    (SMC_GET_GP(gpregs, CTX_GPREG_X2) !=
-				(SPMD_FWK_MSG_BIT |
+				(FFA_FWK_MSG_BIT |
 				 SPMD_FWK_MSG_FFA_VERSION_RESP))) {
 				ERROR("Failed to forward FFA_VERSION\n");
 				ret = FFA_ERROR_NOT_SUPPORTED;