refactor: rename type for FF-A IDs

The FF-A ID is a unsigned 16-bit value that was named
ffa_vm_id_t. This patch changes it to simply ffa_id_t.
This is to make clearer the ID type is used for other
endpoints other than simply VMs.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I60319c08481b2380bd0063b108a35fc01e2af537
diff --git a/test/linux/hftest_socket.c b/test/linux/hftest_socket.c
index 1ea363a..6957045 100644
--- a/test/linux/hftest_socket.c
+++ b/test/linux/hftest_socket.c
@@ -88,8 +88,8 @@
 		swap(&(hdr->src_port), &(hdr->dst_port));
 
 		/* Swap the destination and source ids. */
-		ffa_vm_id_t dst_id = ffa_sender(ret);
-		ffa_vm_id_t src_id = ffa_receiver(ret);
+		ffa_id_t dst_id = ffa_sender(ret);
+		ffa_id_t src_id = ffa_receiver(ret);
 
 		EXPECT_EQ(ffa_rx_release().func, FFA_SUCCESS_32);
 		EXPECT_EQ(
diff --git a/test/linux/linux.c b/test/linux/linux.c
index bfc912d..1b5ce1e 100644
--- a/test/linux/linux.c
+++ b/test/linux/linux.c
@@ -75,7 +75,7 @@
  */
 TEST(linux, socket_echo_hafnium)
 {
-	ffa_vm_id_t vm_id = HF_VM_ID_OFFSET + 1;
+	ffa_id_t vm_id = HF_VM_ID_OFFSET + 1;
 	int port = 10;
 	int socket_id;
 	struct hf_sockaddr addr;