Add support to 'perf report' annotate view or 'perf annotate --stdio2'
to aggregate the IPC derived from timed LBRs per symbol. We compute the
average IPC and the IPC coverage percentage.

For example:

  $ perf annotate --stdio2

  Percent  IPC Cycle (Average IPC: 2.30, IPC Coverage: 54.8%)

                          Disassembly of section .text:

                          000000000003aac0 <random@@GLIBC_2.2.5>:
    8.32  3.28              sub    $0x18,%rsp
          3.28              mov    $0x1,%esi
          3.28              xor    %eax,%eax
          3.28              cmpl   $0x0,argp_program_version_hook@@GLIBC_2.2.5+0x1e0
   11.57  3.28     1      ↓ je     20
                            lock   cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
                          ↓ jne    29
                          ↓ jmp    43
   11.57  1.10        20:   cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
    0.00  1.10     1      ↓ je     43
                      29:   lea    __abort_msg@@GLIBC_PRIVATE+0x8a0,%rdi
                            sub    $0x80,%rsp
                          → callq  __lll_lock_wait_private
                            add    $0x80,%rsp
    0.00  3.00        43:   lea    __ctype_b@GLIBC_2.2.5+0x38,%rdi
          3.00              lea    0xc(%rsp),%rsi
    8.49  3.00     1      → callq  __random_r
    7.91  1.94              cmpl   $0x0,argp_program_version_hook@@GLIBC_2.2.5+0x1e0
    0.00  1.94     1      ↓ je     68
                            lock   decl   __abort_msg@@GLIBC_PRIVATE+0x8a0
                          ↓ jne    70
                          ↓ jmp    8a
    0.00  2.00        68:   decl   __abort_msg@@GLIBC_PRIVATE+0x8a0
   21.56  2.00     1      ↓ je     8a
                      70:   lea    __abort_msg@@GLIBC_PRIVATE+0x8a0,%rdi
                            sub    $0x80,%rsp
                          → callq  __lll_unlock_wake_private
                            add    $0x80,%rsp
   21.56  2.90        8a:   movslq 0xc(%rsp),%rax
          2.90              add    $0x18,%rsp
    9.03  2.90     1      ← retq

It shows for this symbol the average IPC is 2.30 and the IPC coverage is
54.8%.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1543586097-27632-2-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>