selftests/bpf: Don't include .d files on make clean

Ignore generated %.test.o dependencies when make goal is clean or
docs-clean.

Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/all/oNTIdax7aWGJdEgabzTqHzF4r-WTERrV1e1cNaPQMp-UhYUQpozXqkbuAlLBulczr6I99-jM5x3dxv56JJowaYBkm765R9Aa9kyrVuCl_kA=@pm.me
Link: https://lore.kernel.org/bpf/K69Y8OKMLXBWR0dtOfsC4J46-HxeQfvqoFx1CysCm7u19HRx4MB6yAKOFkM6X-KAx2EFuCcCh_9vYWpsgQXnAer8oQ8PMeDEuiRMYECuGH4=@pm.me

tools/testing/selftests/bpf/Makefile

@@ -608,7 +608,9 @@ $(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d:			\
 			    $(TRUNNER_BPF_SKELS_LINKED)			\
 			    $$(BPFOBJ) | $(TRUNNER_OUTPUT)
 
+ifeq ($(filter clean docs-clean,$(MAKECMDGOALS)),)
 include $(wildcard $(TRUNNER_TEST_OBJS:.o=.d))
+endif
 
 $(TRUNNER_EXTRA_OBJS): $(TRUNNER_OUTPUT)/%.o:				\
 		       %.c						\