Added encode API for SetTID cmd

Added encode API for SetTID command(0x01) which is defined in
DSP0240 Version 1.1.0 sec:8.1.1.

Signed-off-by: Gilbert Chen <gilbertc@nvidia.com>
Change-Id: Ia2d5c76e8ad545e794c72f5963556f1f0e6357fc
diff --git a/src/base.c b/src/base.c
index 9a5ae09..86bacea 100644
--- a/src/base.c
+++ b/src/base.c
@@ -398,6 +398,33 @@
 	return PLDM_SUCCESS;
 }
 
+int encode_set_tid_req(uint8_t instance_id, uint8_t tid, struct pldm_msg *msg)
+{
+	if (msg == NULL) {
+		return PLDM_ERROR_INVALID_DATA;
+	}
+
+	if (tid == 0x0 || tid == 0xff) {
+		return PLDM_ERROR_INVALID_DATA;
+	}
+
+	struct pldm_header_info header = {0};
+	header.instance = instance_id;
+	header.msg_type = PLDM_REQUEST;
+	header.command = PLDM_SET_TID;
+
+	uint8_t rc = pack_pldm_header(&header, &(msg->hdr));
+	if (rc != PLDM_SUCCESS) {
+		return rc;
+	}
+
+	struct pldm_set_tid_req *request =
+	    (struct pldm_set_tid_req *)msg->payload;
+	request->tid = tid;
+
+	return PLDM_SUCCESS;
+}
+
 int decode_multipart_receive_req(
     const struct pldm_msg *msg, size_t payload_length, uint8_t *pldm_type,
     uint8_t *transfer_opflag, uint32_t *transfer_ctx, uint32_t *transfer_handle,