selftests/bpf: Simplify the calculation of variables

Fix the following coccicheck warnings:

./tools/testing/selftests/bpf/test_sockmap.c:735:35-37: WARNING !A || A
&& B is equivalent to !A || B.

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Jiapeng Chong <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/testing/selftests/bpf/test_sockmap.c

···
 		 * socket is not a valid test. So in this case lets not
 		 * enable kTLS but still run the test.
 		 */
-		if (!txmsg_redir || (txmsg_redir && txmsg_ingress)) {
+		if (!txmsg_redir || txmsg_ingress) {
 			err = sockmap_init_ktls(opt->verbose, rx_fd);
 			if (err)
 				return err;