SELinux: silence build warning when !CONFIG_BUG

If one builds a kernel without CONFIG_BUG there are a number of 'may be
used uninitialized' warnings. Silence these by returning after the BUG().

Signed-off-by: Eric Paris <[e-mail]>
Reviewed-by: James Morris <[e-mail]>

security/selinux/hooks.c

···
 			continue;
 		default:
 			BUG();
+			return;
 		};
 		/* we need a comma before each option */
 		seq_putc(m, ',');
···
 		printk(KERN_ERR
 		       "SELinux:  out of range capability %d\n", cap);
 		BUG();
+		return -EINVAL;
 	}
 
 	rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);

security/selinux/netnode.c

···
 		break;
 	default:
 		BUG();
+		return NULL;
 	}
 
 	list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)