tiny fixup: depend on :skx

Change-Id: I792f79eb99106b36b8a53af01ee55898bd2041ac
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294566
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Herb Derby <herb@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 3c0405d..15249b9 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -932,6 +932,7 @@
     ":raw",
     ":sksl_interpreter",
     ":skvm_jit",
+    ":skx",
     ":sse2",
     ":sse41",
     ":sse42",