kprobes: Remove redundant text_mutex lock in optimize

Remove text_mutex locking in optimize_all_kprobes, because
this function doesn't modify text. It simply queues probes on
optimization list for kprobe_optimizer worker thread.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101025131801.19160.70939.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>