Remove redundant check when encountering fragCoord in IR generator

Change-Id: Ifa364ee754fed40160bd161aea60ead2e9fb8414
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/245616
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed