staging/lustre/ptlrpc: Remove __ptlrpc_request_bufs_pack

Combine __ptlrpc_request_bufs_pack into ptlrpc_request_bufs_pack
because it was an unnecessary wrapper otherwise.

Signed-off-by: Ben Evans <bevans@cray.com>
Reviewed-on: http://review.whamcloud.com/16765
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7269


Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Chris Horn <hornc@cray.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>