perf probe: Add bitfield member support

Add bitfield member accessing support to probe arguments.

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20110204125211.9507.60265.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ committer note: Fixed up '%lu' use for return of BYTES_TO_BITS ('%zd') ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>