[graphite] Reduce fIntrinsicConstantBuffer size

Reduce fIntrinsicConstantBuffer size to remove any padding bytes at
the end of the buffer.

Bug: chromium:1485789
Change-Id: Ibbbe982a571ede2513e20abf6241984be48619ef
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/805796
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Auto-Submit: Peng Huang <penghuang@chromium.org>
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
2 files changed