chore(memory share): comments on validate retrieve

Rewrite a few comments in the function to validate the retrieve request.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I194af398555aa7e33ffd8a6545d74a635e401a9f
diff --git a/src/ffa_memory.c b/src/ffa_memory.c
index c441c4c..ed21a7d 100644
--- a/src/ffa_memory.c
+++ b/src/ffa_memory.c
@@ -2448,6 +2448,8 @@
 		 * In case there is only one borrower from the NWd in the
 		 * transaction descriptor, record that in the `receiver_id` for
 		 * later use, and validate in the retrieve request message.
+		 * This limitation is due to the fact SPMC can't determine the
+		 * index in the memory share structures state to update.
 		 */
 		if (to_locked.vm->id == HF_HYPERVISOR_VM_ID) {
 			uint32_t other_world_count = 0;
@@ -2472,8 +2474,7 @@
 		/*
 		 * Validate retrieve request, according to what was sent by the
 		 * sender. Function will output the `receiver_index` from the
-		 * provided memory region, and will output `permissions` from
-		 * the validated requested permissions.
+		 * provided memory region.
 		 */
 		ret = ffa_memory_retrieve_validate(
 			receiver_id, retrieve_request, memory_region,
@@ -2491,6 +2492,12 @@
 			goto out;
 		}
 
+		/*
+		 * Validate the requested permissions against the sent
+		 * permissions.
+		 * Outputs the permissions to give to retriever at S2
+		 * PTs.
+		 */
 		ret = ffa_memory_retrieve_validate_memory_access_list(
 			memory_region, retrieve_request, receiver_id,
 			&permissions);