i965: Remove broken non-interleaved-to-interleaved upload code.

i965: Remove broken non-interleaved-to-interleaved upload code.

This failed when all the uploads to occur were uniform-type vertex data (like
glColor4f being active across a DrawArrays), because it would upload 1 element
instead of 1 element per vertex.  There was no citation for how this code
helped any particular application, and it breaks ETQW, so just remove it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47170
NOTE: This is a candidate for the 9.0 and 8.0 branches.
Reviewed-and-tested-by: Kenneth Graunke <kenneth@whitecape.org>