Only revisions < 4.0 don't have a functional wait instruction.
From Thomas Koeller (Thomas.Koeller@baslerweb.com).
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
        case CPU_R5000:
        case CPU_NEVADA:
        case CPU_RM7000:
-       case CPU_RM9000:
        case CPU_4KC:
        case CPU_4KEC:
        case CPU_4KSC:
                } else
                        printk(" unavailable.\n");
                break;
+       case CPU_RM9000:
+               if ((c->processor_id & 0x00ff) >= 0x40) {
+                       cpu_wait = r4k_wait;
+                       printk(" available.\n");
+               } else {
+                       printk(" unavailable.\n");
+               }
+               break;
        default:
                printk(" unavailable.\n");
                break;