staging/lustre: Replace last users of OBD_ALLOC/FREE_LARGE

OBD_ALLOC_LARGE is now replaced with libcfs_kvzalloc and
OBD_FREE_LARGE is now replaced with kvfree.

Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>