perf tools: Add ia64 support for tools/perf/

Compiler on ia64 rejects the "-m64" option.
Add arch specific pieces to perf.h

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4b02d7f43514327a@agluck-desktop.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>