selftests/bpf: Install all required files to run selftests

When installing the selftests using
"make -C tools/testing/selftests install", we need to make sure
all the required files to run the selftests are installed. Let's
make sure this is the case.
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221205131618.1524337-2-daan.j.demeyer@gmail.com

tools/testing/selftests/bpf/Makefile

@@ -532,8 +532,10 @@ TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/bpf_testmod.ko	\
 		       $(OUTPUT)/liburandom_read.so			\
 		       $(OUTPUT)/xdp_synproxy				\
 		       $(OUTPUT)/sign-file				\
-		       ima_setup.sh verify_sig_setup.sh			\
-		       $(wildcard progs/btf_dump_test_case_*.c)
+		       ima_setup.sh 					\
+		       verify_sig_setup.sh				\
+		       $(wildcard progs/btf_dump_test_case_*.c)		\
+		       $(wildcard progs/*.bpf.o)
 TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
 TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS) -DENABLE_ATOMICS_TESTS
 $(eval $(call DEFINE_TEST_RUNNER,test_progs))