Remove unused variable from IR generator

Change-Id: Ib97cbf2e20580d3b9e54a5ffe793013ec97d4892
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/321539
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
2 files changed