tnl: Code formatting in t_rebase.c

tnl: Code formatting in t_rebase.c

Many little changes.  Almost everything is indentation or removal of
trailing whitespace.  Some places move a loop variable declaration to
the loop.  Some comments either re-wrapped or converted to single
line.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4512>