staging: lustre: remove cfs_task_state_t

It's just a long, so remove the typedef and use long.

Side note, all the functions like waitq_* should be removed as well,
they are wrapping functions that don't really do what it seems that they
do based on their name.

Cc: Peng Tao <tao.peng@emc.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>