tools: bpf: remove feature detection output

bpf tools use feature detection for libbfd dependency, clean up
the output files on make clean.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/bpf/bpftool/Makefile

@@ -89,6 +89,8 @@ $(OUTPUT)%.o: %.c
 clean: $(LIBBPF)-clean
 	$(call QUIET_CLEAN, bpftool)
 	$(Q)$(RM) $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d
+	$(call QUIET_CLEAN, core-gen)
+	$(Q)$(RM) $(OUTPUT)FEATURE-DUMP.bpftool
 
 install: $(OUTPUT)bpftool
 	$(call QUIET_INSTALL, bpftool)