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/spm/el3_spmc/spmc.mk b/services/std_svc/spm/el3_spmc/spmc.mk
index 8067c74..9f82ccb 100644
--- a/services/std_svc/spm/el3_spmc/spmc.mk
+++ b/services/std_svc/spm/el3_spmc/spmc.mk
@@ -11,7 +11,8 @@
 SPMC_SOURCES	:=	$(addprefix services/std_svc/spm/el3_spmc/,	\
 			spmc_main.c				\
 			spmc_setup.c				\
-			logical_sp.c)
+			logical_sp.c				\
+			spmc_pm.c)
 
 # Specify platform specific logical partition implementation.
 SPMC_LP_SOURCES  := $(addprefix ${PLAT_DIR}/, \