tools lib bpf: Fix double file test in Makefile

The Makefile verifies the same file exists twice:
  test -f ../../../include/uapi/linux/bpf.h -a \
       -f ../../../include/uapi/linux/bpf.h

The purpose of the check is to ensure the diff (immediately after the
test) doesn't fail with these two files:

  tools/include/uapi/linux/bpf.h
  include/uapi/linux/bpf.h

Same recipe for bpf_common:
  test -f ../../../include/uapi/linux/bpf_common.h -a \
       -f ../../../include/uapi/linux/bpf_common.h

This corrects the location of the tests.
Signed-off-by: Daniel Díaz <daniel.diaz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1502814810-960-1-git-send-email-daniel.diaz@linaro.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/bpf/Makefile

@@ -154,10 +154,10 @@ all: fixdep $(VERSION_FILES) all_cmd
 all_cmd: $(CMD_TARGETS)
 
 $(BPF_IN): force elfdep bpfdep
-	@(test -f ../../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
+	@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
 	(diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \
 	echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true
-	@(test -f ../../../include/uapi/linux/bpf_common.h -a -f ../../../include/uapi/linux/bpf_common.h && ( \
+	@(test -f ../../include/uapi/linux/bpf_common.h -a -f ../../../include/uapi/linux/bpf_common.h && ( \
 	(diff -B ../../include/uapi/linux/bpf_common.h ../../../include/uapi/linux/bpf_common.h >/dev/null) || \
 	echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf_common.h' differs from latest version at 'include/uapi/linux/bpf_common.h'" >&2 )) || true
 	$(Q)$(MAKE) $(build)=libbpf