lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()

Not a big deal, but since other __get_key_name() callers
use it lets be consistent.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20121020190519.GH25467@moon
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --cc kernel/lockdep_proc.c
Simple merge