intel: aubinator: remove standard input processing option

intel: aubinator: remove standard input processing option

On a follow up commit in this series, we stop copying the data from
the mmap'ed file into our big gtt mmap, and start referencing data in
it directly. So reallocating the read buffer and adding more data from
stdin wouldn't work. For that reason, let's stop supporting stdin
process.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rafael Antognolli <rafael.antognolli@intel.com>