use #ifdef instead of #if for SK_VULKAN

Try to fix android roll

Bug: skia:
Change-Id: Iae32027b299d8a975d3caf70f0f8910541ca972d
Reviewed-on: https://skia-review.googlesource.com/19800
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed