selinux: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/hooks.c

@@ -4036,6 +4036,7 @@ static int selinux_kernel_load_data(enum kernel_load_data_id id, bool contents)
 	switch (id) {
 	case LOADING_MODULE:
 		rc = selinux_kernel_module_from_file(NULL);
+		break;
 	default:
 		break;
 	}