tools/bpf: Move linux/types.h for selftests and bpftool

Commit fe4eb069ed ("bpftool: Use linux/types.h from source tree for
profiler build") added a build dependency on tools/testing/selftests/bpf
to tools/bpf/bpftool. This is suboptimal with respect to a possible
stand-alone build of bpftool.

Fix this by moving tools/testing/selftests/bpf/include/uapi/linux/types.h
to tools/include/uapi/linux/types.h.

This requires an adjustment in the include search path order for the
tests in tools/testing/selftests/bpf so that tools/include/linux/types.h
is selected when building host binaries and
tools/include/uapi/linux/types.h is selected when building bpf binaries.

Verified by compiling bpftool and the bpf selftests on x86_64 with this
change.

Fixes: fe4eb069ed ("bpftool: Use linux/types.h from source tree for profiler build")
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200313113105.6918-1-tklauser@distanz.ch

tools/bpf/bpftool/Makefile

@@ -129,7 +129,6 @@ $(OUTPUT)_bpftool: $(_OBJS) $(LIBBPF)
 skeleton/profiler.bpf.o: skeleton/profiler.bpf.c $(LIBBPF)
 	$(QUIET_CLANG)$(CLANG) \
 		-I$(srctree)/tools/include/uapi/ \
-		-I$(srctree)/tools/testing/selftests/bpf/include/uapi \
 		-I$(LIBBPF_PATH) -I$(srctree)/tools/lib \
 		-g -O2 -target bpf -c $< -o $@