update include path for SkBlurMask.h

fixes https://skia-review.googlesource.com/c/skia/+/113463

Bug: skia:
Change-Id: I78abc53bd802286e9fc65487551db17a2c737e1a
Reviewed-on: https://skia-review.googlesource.com/113715
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed