perf tools: Fix parsers' rules to dependencies

Currently the parsers objects (bison/flex related) are each time perf
is built. No matter the generated files are already in place, the
parser generation is executed every time.

Changing the rules to have proper flex/bison objects generation
dependencies.

The parsers code is not rebuilt until the flex/bison source files
are touched. Also when flex/bison source is changed, only dependent
objects are rebuilt.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.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>
Link: http://lkml.kernel.org/r/1334140791-3024-1-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>