dxc: Fix gn check for :TableGen

Change-Id: Ib32ea042502e09a3b8d137c2dd3cdcac9e00883f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/140560
Commit-Queue: Austin Eng <enga@chromium.org>
Kokoro: Austin Eng <enga@chromium.org>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
diff --git a/third_party/gn/dxc/BUILD.gn b/third_party/gn/dxc/BUILD.gn
index 19ed528..e09d1e2 100644
--- a/third_party/gn/dxc/BUILD.gn
+++ b/third_party/gn/dxc/BUILD.gn
@@ -623,7 +623,10 @@
 
 # Common code for both llvm-tblgen and clang-tblgen
 source_set("TableGen") {
-  public_deps = [ ":Support" ]
+  public_deps = [
+    ":DataTypes-header",
+    ":Support",
+  ]
 
   sources = [
     "$dawn_dxc_dir/lib/TableGen/Error.cpp",