feat(spmc): add helper function to obtain hyp structure

We assume that the first descriptor in the normal world
endpoints is reserved for the hypervisor and add a helper
function to enable retrieving this directly.

Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: I67c3589994eb820ef420db6ab7e8bd0825d64455
diff --git a/services/std_svc/spm/el3_spmc/spmc_main.c b/services/std_svc/spm/el3_spmc/spmc_main.c
index 1eb4a30..efa9da8 100644
--- a/services/std_svc/spm/el3_spmc/spmc_main.c
+++ b/services/std_svc/spm/el3_spmc/spmc_main.c
@@ -81,6 +81,15 @@
 	return NULL;
 }
 
+/*
+ * Helper function to obtain the descriptor of the Hypervisor or OS kernel.
+ * We assume that the first descriptor is reserved for this entity.
+ */
+struct ns_endpoint_desc *spmc_get_hyp_ctx(void)
+{
+	return &(ns_ep_desc[0]);
+}
+
 /******************************************************************************
  * This function returns to the place where spmc_sp_synchronous_entry() was
  * called originally.