tools lib traceevent: Fix python/perf.so compiling error

tools lib traceevent: Fix python/perf.so compiling error

'make build-test' finds an error that make_python_perf_so fails due to
missing of libtraceevent-dynamic-list:

 '.../python2' util/setup.py \
   --quiet build_ext; \
   mkdir -p python && \
   cp python_ext_build/lib/perf.so python/
   /path/to/ld: cannot open linker script file /path/to/kernel/tools/lib/traceevent/libtraceevent-dynamic-list: No such file or directory
   collect2: error: ld returned 1 exit status
   error: command 'x86_64-linux-gcc' failed with exit status 1
   cp: cannot stat 'python_ext_build/lib/perf.so': No such file or directory
   make[3]: *** [python/perf.so] Error 1
   make[2]: *** [python/perf.so] Error 2
     test: test -f ./python/perf.so
     make[1]: *** [make_python_perf_so] Error 1
     make: *** [build-test] Error 2
     make: Leaving directory `/path/to/kernel/tools/perf'

This is caused by commit e3d09ec8126fe2c9a3ade661e2126e215ca27a80
("tools lib traceevent: Export dynamic symbols used by traceevent
plugins") that, it adds the list file to LDFLAGS but forgot to add it to
dependency list of python/perf.so.

This patch fixes this problem.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1434079031-123162-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>