perf report: Print out raw events in hexa

Print out events in hexa dump format, when -D is specified:

0x4868 [0x48]: event: 1
.
. ... raw event: size 72 bytes
.  0000:  01 00 00 00 00 00 48 00 d4 72 00 00 d4 72 00 00  ......H..r...r.
.  0010:  00 00 40 f2 3e 00 00 00 00 30 01 00 00 00 00 00  ..@.>....0.....
.  0020:  00 00 00 00 00 00 00 00 2f 75 73 72 2f 6c 69 62  ......../usr/li
.  0030:  36 34 2f 6c 69 62 65 6c 66 2d 30 2e 31 34 31 2e  64/libelf-0.141
.  0040:  73 6f 00 00 00 00 00 00                          f-0.141
.
0x4868 [0x48]: PERF_EVENT_MMAP 29396: [0x3ef2400000(0x13000) @ (nil)]: /usr/lib64/libelf-0.141.so

This helps the debugging of mis-parsing of data files, and helps
the addition of new sample/trace formats.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>