perf tools: Fix build dependency of perf python extension

perf tools: Fix build dependency of perf python extension

The perf python extention (perf.so) file lacks its dependencies in the
Makefile so that it cannot be refreshed if one of source files it depends
is changed. Fix it by putting them in a separate file and processing it in
both of Makefile and setup.py.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1329043524-12470-1-git-send-email-namhyung@gmail.com
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>