staging: lustre: make ptlrpc_init static

fix sparse warning in lustre/ptlrpc/ptlrpc_module.c:54:12:
     warning: symbol 'ptlrpc_init' was not declared. Should it be static?

The __init macro is moved before the function name to match standard usage.

Signed-off-by: Matt Mooney <mfm@muteddisk.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>