[MIPS] 74K: Assume it will also have an AR bit in config7

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 33b1451..75d887e 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1009,6 +1009,7 @@
 		break;
 	case CPU_24K:
 	case CPU_34K:
+	case CPU_74K:
 		if ((read_c0_config7() & (1 << 16))) {
 			/* effectively physically indexed dcache,
 			   thus no virtual aliases. */