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/x86/kernel/cpu/mcheck/p5.c

@@ -33,7 +33,7 @@ static void pentium_machine_check(struct pt_regs *regs, long error_code)
 			smp_processor_id());
 	}
 
-	add_taint(TAINT_MACHINE_CHECK);
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */