drm/radeon/kms: allow R500 regs VAP_ALT_NUM_VERTICES and VAP_INDEX_OFFSET

[airlied: fix V_A_N_V to not be safe and fix check to make sure only r500
 - bump userspace version]

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index e40dbdc..c06207e 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -3011,7 +3011,11 @@
 		}
 	}
 	prim_walk = (track->vap_vf_cntl >> 4) & 0x3;
-	nverts = (track->vap_vf_cntl >> 16) & 0xFFFF;
+	if (track->vap_vf_cntl & (1 << 14)) {
+		nverts = track->vap_alt_nverts;
+	} else {
+		nverts = (track->vap_vf_cntl >> 16) & 0xFFFF;
+	}
 	switch (prim_walk) {
 	case 1:
 		for (i = 0; i < track->num_arrays; i++) {