Remove last SK_GANESH #ifdefs from non-Ganesh SkImage code

Change-Id: Ic546e0dea6108ba38b1dcc230870b54dc5db8719
Bug: skia:13983
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/684578
Owners-Override: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
7 files changed