perf tools: Enable LBR call stack support

Currently, there are two call chain recording options, fp and dwarf.

Haswell has a new feature that utilizes the existing LBR facility to
record call chains. Kernel side LBR support code provides this as a
third option to record call chains. This patch enables the lbr call
stack support on the tooling side.

LBR call stack has some limitations:

 - It reuses current LBR facility, so LBR call stack and branch record
   can not be enabled at the same time.

 - It is only available for user-space callchains.

However, it also offers some advantages:

 - LBR call stack can work on user apps which don't have frame-pointers
   or dwarf debug info compiled. It is a good alternative when nothing
   else works.

Tested-by: Jiri Olsa <[email protected]>
Signed-off-by: Kan Liang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Cody P Schafer <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Jacob Shin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masanari Iida <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Rodrigo Campos <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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