staging: lustre: remove m_ prefix from function pointers

All the callers call these function pointers without the "m_" prefix and
use macro magic to add it later behind the scenes.  It means that you
can't grep for the call sites.  I considered modifying the call sites
but in the end I decided that the "m_" prefix doesn't add anything so we
can just get rid of it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>