taint: add explicit flag to show whether lock dep is still OK.

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

arch/m68k/kernel/traps.c

@@ -1176,7 +1176,7 @@ void die_if_kernel (char *str, struct pt_regs *fp, int nr)
 	console_verbose();
 	printk("%s: %08x\n",str,nr);
 	show_registers(fp);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	do_exit(SIGSEGV);
 }