staging: lustre: cl_io: Remove cl_lock_descr_fid wrapper

Remove unnecessary wrapper function cl_lock_descr_fid() and replace all
its calls with the function it wrapped.

Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>