Comment # 7 on bug 93648 from Nicolai H�hnle

The fix is now in Mesa master:

commit 004fcd423011d45f746d571be47062feeea75455
Author: Nicolai H�hnle <nicolai.haehnle@amd.com>
Date:   Fri Jan 22 17:04:48 2016 -0500

    radeonsi: ensure that VGT_GS_MODE is sent when necessary