intel: Add drm_intel_gem_context_get_id to intel-symbols-check

Fixes make check. Trivial.
diff --git a/intel/intel-symbol-check b/intel/intel-symbol-check
index 4462533..038c982 100755
--- a/intel/intel-symbol-check
+++ b/intel/intel-symbol-check
@@ -80,6 +80,7 @@
 drm_intel_gem_bo_wait
 drm_intel_gem_context_create
 drm_intel_gem_context_destroy
+drm_intel_gem_context_get_id
 drm_intel_get_aperture_sizes
 drm_intel_get_eu_total
 drm_intel_get_min_eu_in_pool