perf tools: Fix include order for bison/flex-generated C files

perf tools: Fix include order for bison/flex-generated C files

When we use a separate output directory, we add util/ to the include
path for the generated C files.  However, this is currently added to the
end of the path, behind /usr/include/slang and /usr/include/gtk-2.0 if
use of the respective libraries is enabled.  Thus the '#include
"../perf.h"' in util/parse-events.l can actually include
/usr/include/perf.h if it exists.

Move '-Iutil/' ahead of all the other preprocessor options.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Link: http://lkml.kernel.org/r/1345420039.22400.80.camel@deadeye.wl.decadent.org.uk
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>