staging: lustre: remove LL_PROC_PROTO macro

Spell out what is happening with the proc file functions, it helps to
unwind the call chain mess here.

Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: hpdd-discuss <hpdd-discuss@lists.01.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>