perf tools: Drop CROSS_COMPILE from flex and bison calls

The flex and bison tools generate arch-independent C code so its
binaries are not prefixed with the target-arch prefix. With this patch
the Linux 3.4-rc2 can be successfuly build on OE-Core.
Signed-off-by: NOtavio Salvador <otavio@ossystems.com.br>
Link: http://lkml.kernel.org/r/1334148270-13139-1-git-send-email-otavio@ossystems.com.brSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile

@@ -234,8 +234,8 @@ endif
 
 export PERL_PATH
 
-FLEX = $(CROSS_COMPILE)flex
-BISON= $(CROSS_COMPILE)bison
+FLEX = flex
+BISON= bison
 
 $(OUTPUT)util/parse-events-flex.c: util/parse-events.l
 	$(QUIET_FLEX)$(FLEX) --header-file=$(OUTPUT)util/parse-events-flex.h -t util/parse-events.l > $(OUTPUT)util/parse-events-flex.c