i965/fs: Fix the FS inputs setup when some SF outputs aren't used in the FS.

i965/fs: Fix the FS inputs setup when some SF outputs aren't used in the FS.

If there was an edge flag or a two-side-color pair present, we'd end up
mismatched and read values from earlier in the VUE for later FS inputs.

v2: Fix regression in gles2conform shaders generating point size. (change by
    anholt)

Signed-off-by: Olivier Galibert <galibert@pobox.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
NOTE: This is a candidate for the 8.0 branch.