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/spm_common.h b/include/runtime_services/spm_common.h
index 0c8ade1..fc7ddd7 100644
--- a/include/runtime_services/spm_common.h
+++ b/include/runtime_services/spm_common.h
@@ -139,4 +139,9 @@
 bool ffa_partition_info_regs_helper(const struct ffa_uuid uuid,
 		       const struct ffa_partition_info *expected,
 		       const uint16_t expected_size);
+
+struct ffa_memory_access ffa_memory_access_init_permissions_from_mem_func(
+	ffa_id_t receiver_id,
+	uint32_t mem_func);
+
 #endif /* SPM_COMMON_H */