Align const pointer casts in SkRect

Clang5 reports this as a bug.

Bug: skia:
Change-Id: I838b8abf2399429358f83d3232dc9d2caac54967
Reviewed-on: https://skia-review.googlesource.com/26080
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed