selftests/bpf: Do not export subtest as standalone test

Two subtests in ksyms_module.c are not qualified as static, so these
subtests are exported as standalone tests in tests.h and lead to
confusion for the output of "./test_progs -t ksyms_module".

By using the following command ...

grep "^void \(serial_\)\?test_[a-zA-Z0-9_]\+(\(void\)\?)" \
tools/testing/selftests/bpf/prog_tests/*.c | \
awk -F : '{print $1}' | sort | uniq -c | awk '$1 != 1'

... one finds out that other tests also have a similar problem, so
fix these tests by marking subtests in these tests as static.

Signed-off-by: Hou Tao <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/testing/selftests/bpf/prog_tests/ksyms_module.c

···
 #include "test_ksyms_module.lskel.h"
 #include "test_ksyms_module.skel.h"
 
-void test_ksyms_module_lskel(void)
+static void test_ksyms_module_lskel(void)
 {
 	struct test_ksyms_module_lskel *skel;
 	int err;
···
 	test_ksyms_module_lskel__destroy(skel);
 }
 
-void test_ksyms_module_libbpf(void)
+static void test_ksyms_module_libbpf(void)
 {
 	struct test_ksyms_module *skel;
 	int err;

tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c

···
 #include <test_progs.h>
 #include <network_helpers.h>
 
-void test_xdp_update_frags(void)
+static void test_xdp_update_frags(void)
 {
 	const char *file = "./test_xdp_update_frags.o";
 	struct bpf_program *prog;

tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c

···
 	bpf_object__close(obj);
 }
 
-void test_xdp_adjust_frags_tail_shrink(void)
+static void test_xdp_adjust_frags_tail_shrink(void)
 {
 	const char *file = "./test_xdp_adjust_tail_shrink.o";
 	__u32 exp_size;
···
 	bpf_object__close(obj);
 }
 
-void test_xdp_adjust_frags_tail_grow(void)
+static void test_xdp_adjust_frags_tail_grow(void)
 {
 	const char *file = "./test_xdp_adjust_tail_grow.o";
 	__u32 exp_size;

tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c

···
 
 #define IFINDEX_LO	1
 
-void test_xdp_with_cpumap_helpers(void)
+static void test_xdp_with_cpumap_helpers(void)
 {
 	struct test_xdp_with_cpumap_helpers *skel;
 	struct bpf_prog_info info = {};
···
 	test_xdp_with_cpumap_helpers__destroy(skel);
 }
 
-void test_xdp_with_cpumap_frags_helpers(void)
+static void test_xdp_with_cpumap_frags_helpers(void)
 {
 	struct test_xdp_with_cpumap_frags_helpers *skel;
 	struct bpf_prog_info info = {};

tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c

···
 	}
 }
 
-void test_xdp_with_devmap_frags_helpers(void)
+static void test_xdp_with_devmap_frags_helpers(void)
 {
 	struct test_xdp_with_devmap_frags_helpers *skel;
 	struct bpf_prog_info info = {};