20Kc and SB1 don't suffer from aliases.

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/mm/c-r4k.c

@@ -1012,8 +1012,10 @@ static void __init probe_pcache(void)
 	 * with that for us so we don't need to take care ourselves.
 	 */
 	switch (c->cputype) {
+	case CPU_20KC:
 	case CPU_R10000:
 	case CPU_R12000:
+	case CPU_SB1:
 		break;
 	case CPU_24K:
 		if (!(read_c0_config7() & (1 << 16)))