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>
diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
index acfaf4c..1ea5459 100644
--- a/tools/bpf/Makefile
+++ b/tools/bpf/Makefile
@@ -81,6 +81,8 @@
 	$(call QUIET_CLEAN, bpf-progs)
 	$(Q)rm -rf $(OUTPUT)*.o $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg \
 	       $(OUTPUT)bpf_asm $(OUTPUT)bpf_exp.yacc.* $(OUTPUT)bpf_exp.lex.*
+	$(call QUIET_CLEAN, core-gen)
+	$(Q)rm -f $(OUTPUT)FEATURE-DUMP.bpf
 
 install: $(PROGS) bpftool_install
 	$(call QUIET_INSTALL, bpf_jit_disasm)