Fix the following coccicheck warning:

./tools/testing/selftests/bpf/progs/fentry_test.c:76:15-16: WARNING
comparing pointer to 0.

Reported-by: Abaci Robot <redacted>
Signed-off-by: Jiapeng Chong <redacted>
---
  tools/testing/selftests/bpf/progs/fentry_test.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
index 5f645fd..d4247d6 100644
--- a/tools/testing/selftests/bpf/progs/fentry_test.c
+++ b/tools/testing/selftests/bpf/progs/fentry_test.c

@@ -64,7 +64,7 @@ struct bpf_fentry_test_t {
  SEC("fentry/bpf_fentry_test7")
  int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
  {
-	if (arg == 0)
+	if (!arg)
  		test7_result = 1;
  	return 0;
  }

@@ -73,7 +73,7 @@ int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
  SEC("fentry/bpf_fentry_test8")
  int BPF_PROG(test8, struct bpf_fentry_test_t *arg)
  {
-	if (arg->a == 0)
+	if (!arg->a)
  		test8_result = 1;
  	return 0;
  }