drm/amd/display: fix double assignment to msg_id field

The msg_id field is being assigned twice. Fix this by replacing the second
assignment with an assignment to msg_size.

Addresses-Coverity: ("Unused value")
Fixes: 11a00965 ("drm/amd/display: Add PSP block to verify HDCP2.2 steps")
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c

@@ -42,7 +42,7 @@ static void hdcp2_message_init(struct mod_hdcp *hdcp,
 	in->process.msg2_desc.msg_id = TA_HDCP_HDCP2_MSG_ID__NULL_MESSAGE;
 	in->process.msg2_desc.msg_size = 0;
 	in->process.msg3_desc.msg_id = TA_HDCP_HDCP2_MSG_ID__NULL_MESSAGE;
-	in->process.msg3_desc.msg_id = 0;
+	in->process.msg3_desc.msg_size = 0;
 }
 enum mod_hdcp_status mod_hdcp_remove_display_topology(struct mod_hdcp *hdcp)
 {