Fix include path in spirv-tools build

Change-Id: Ia47127d5f539f6eb479c095f7bf9079db1ff5bad
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/237120
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Herb Derby <herb@google.com>
1 file changed