staging:lustre: Replace max() with max_t()

Replace max() with max_t() in accordance to chekpatch.pl warning in
lov_obd.c.

Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>