refactor(spm): `ffa_memory_access` constructors

Add `ffa_memory_access_init_permissions` and
`ffa_memory_access_init_permissions_from_mem_func` helpers.

Change-Id: I9a5bb09e7f230a65decff7f58a0c188aff3e7449
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
diff --git a/include/runtime_services/ffa_helpers.h b/include/runtime_services/ffa_helpers.h
index 4f2bb02..91a7a6e 100644
--- a/include/runtime_services/ffa_helpers.h
+++ b/include/runtime_services/ffa_helpers.h
@@ -728,6 +728,12 @@
 struct ffa_value ffa_partition_info_get_regs(const struct ffa_uuid uuid,
 					     const uint16_t start_index,
 					     const uint16_t tag);
+
+struct ffa_memory_access ffa_memory_access_init_permissions(
+	ffa_id_t receiver_id, enum ffa_data_access data_access,
+	enum ffa_instruction_access instruction_access,
+	ffa_memory_receiver_flags_t flags);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* FFA_HELPERS_H */