feat: check if a partition is discoverable during its lifetime

This patch adds provision to check if a partition is discoverable during
its lifetime through FFA_PARTITION_INFO_GET interface. A partition
becomes undiscoverable if all its execution contexts have moved to NULL
state.

Change-Id: I99adfbc7eccaaf1dc3cf13a68fcff8f5c86fad02
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
diff --git a/src/api.c b/src/api.c
index 705834c..4032655 100644
--- a/src/api.c
+++ b/src/api.c
@@ -550,6 +550,10 @@
 	for (ffa_vm_count_t vm_idx = 0; vm_idx < vm_get_count(); vm_idx++) {
 		struct vm *vm = vm_find_index(vm_idx);
 
+		if (!vm_is_discoverable(vm)) {
+			continue;
+		}
+
 		for (size_t uuid_idx = 0; uuid_idx < PARTITION_MAX_UUIDS;
 		     uuid_idx++) {
 			struct ffa_uuid uuid = vm->uuids[uuid_idx];