perf tools: Add missing files to build the python binding

Changeset 0f6a3015:
"perf tools: Support user regs and stack in sample parsing"

uses hweight_long in evsel.c, so we need to drag util/hweight.c
to the python binding.

Ditto for ee8dd3ca:
"perf tools: Change strlist to use the new rblist"

where we need to add util/rblist.c.

Now twatch.py works again:

 # export PYTHONPATH=~acme/git/build/perf/python/
 # ~acme/git/linux/tools/perf/python/twatch.py
 cpu:  4, pid: 23639, tid: 23639 { type: fork, pid: 30659, ppid: 23639, tid: 30659, ptid: 23639, time: 36287872076780}
 cpu:  5, pid: 30659, tid: 30659 { type: comm, pid: 30659, tid: 30659, comm: ls }
 cpu:  5, pid: 30659, tid: 30659 { type: exit, pid: 30659, ppid: 30659, tid: 30659, ptid: 30659, time: 36287873681539}
 cpu:  4, pid: 23639, tid: 23639 { type: fork, pid: 30660, ppid: 23639, tid: 30660, ptid: 23639, time: 36291720420480}
 cpu:  5, pid: 30659, tid: 30659 { type: exit, pid: 30659, ppid: 30659, tid: 30659, ptid: 30659, time: 36287873685714}
 cpu:  5, pid: 30660, tid: 30660 { type: comm, pid: 30660, tid: 30660, comm: git }
 ^C
 KeyboardInterrupt

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-gmq82zp5blin9aml9g5tzokr@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/python-ext-sources

@@ -10,10 +10,12 @@ util/ctype.c
 util/evlist.c
 util/evsel.c
 util/cpumap.c
+util/hweight.c
 util/thread_map.c
 util/util.c
 util/xyarray.c
 util/cgroup.c
 util/debugfs.c
+util/rblist.c
 util/strlist.c
 ../../lib/rbtree.c