drm/radeon/kms/r100: fix bug in CS parser

The first dword of PACKET3_3D_DRAW_IMMD maps to
SE_VTX_FMT so the vertex size is part of the draw
packet.

This patch fixes a possible case where you have a
command buffer that does not contain SE_VTX_FMT
register write, but does contain PACKET3_3D_DRAW_IMMD.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/gpu/drm/radeon/r100.c

@@ -1504,6 +1504,7 @@ static int r100_packet3_check(struct radeon_cs_parser *p,
 			DRM_ERROR("PRIM_WALK must be 3 for IMMD draw\n");
 			return -EINVAL;
 		}
+		track->vtx_size = r100_get_vtx_size(radeon_get_ib_value(p, idx + 0));
 		track->vap_vf_cntl = radeon_get_ib_value(p, idx + 1);
 		track->immd_dwords = pkt->count - 1;
 		r = r100_cs_track_check(p->rdev, track);