Fix variable names in convolve_vertical().

These new names reflect the actual pixels stored in each register.

Change-Id: I8e626196cd8bcbef622e4fb87ac3566a79d3573a
Reviewed-on: https://skia-review.googlesource.com/7624
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Matt Sarett <msarett@google.com>
1 file changed