perf tools: Fix makefile generation under dash

perf tools: Fix makefile generation under dash

Under dash 'echo -n' yields '-n' to stdout.  Use printf "" instead.

Signed-off-by: Sergei Trofimovich <siarheit@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1437298205-29305-1-git-send-email-siarheit@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>