i965/gen7: Use the updated interface for SO write pointer resetting.

The new kernel patch I submitted makes the interface opt-in, so all
batchbuffers aren't preceded by the 4 MI_LOAD_REGISTER_IMMs.  This
requires the updated i915_drm.h present in libdrm 2.4.30.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
diff --git a/configure.ac b/configure.ac
index cc139ad..e5a5e88 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@
 dnl Versions for external dependencies
 LIBDRM_REQUIRED=2.4.24
 LIBDRM_RADEON_REQUIRED=2.4.24
-LIBDRM_INTEL_REQUIRED=2.4.27
+LIBDRM_INTEL_REQUIRED=2.4.30
 LIBDRM_NOUVEAU_REQUIRED=0.6
 DRI2PROTO_REQUIRED=2.6
 GLPROTO_REQUIRED=1.4.14