Cactus: implement hvc call to enable an interrupt

INTERRUPT_ENABLE hvc call can be used by SP to let SPMC(S-EL2) know
about its capability to handle a particular interrupt.

All interrupt specific hvc calls have "interrupt_type" as an argument
to distinguish between IRQ/FIQ. This patch also introduces enum for
interrupt types and modifies spm_interrupt_get() accordingly.

Change-Id: I65e42645330be0787449be850579e1a9fa35127b
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/include/runtime_services/spm_common.h b/include/runtime_services/spm_common.h
index 2d6e51a..a32e8fb 100644
--- a/include/runtime_services/spm_common.h
+++ b/include/runtime_services/spm_common.h
@@ -17,6 +17,12 @@
 /* ID for the first Secure Partition. */
 #define SPM_VM_ID_FIRST                 SP_ID(1)
 
+/** IRQ/FIQ pin used for signaling a virtual interrupt. */
+enum interrupt_pin {
+	INTERRUPT_TYPE_IRQ,
+	INTERRUPT_TYPE_FIQ,
+};
+
 /*
  * The bit 15 of the FF-A ID indicates whether the partition is executing
  * in the normal world, in case it is a Virtual Machine (VM); or in the