sched_ext: tools: Removing duplicate targets during non-cross compilation

When cross-compilation is not used, BPFOBJ and HOST_BPFOBJ are identical
files, libbpf.a, and duplicate libbpf.a files should be removed.

Signed-off-by: Rong Tao <[e-mail]>
Signed-off-by: Tejun Heo <[e-mail]>

tools/sched_ext/Makefile

···
 	$(call msg,MKDIR,,$@)
 	$(Q)mkdir -p $@
 
+ifneq ($(CROSS_COMPILE),)
 $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)			\
 	   $(APIDIR)/linux/bpf.h						\
 	   | $(OBJ_DIR)/libbpf
···
 		    EXTRA_CFLAGS='-g -O0 -fPIC'					\
 		    LDFLAGS="$(LDFLAGS)"					\
 		    DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
+endif
 
 $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		\
 	   $(APIDIR)/linux/bpf.h						\