selftests/powerpc: Make using_hash_mmu() work on Cell & PowerMac

These platforms don't show the MMU in /proc/cpuinfo, but they always
use hash, so teach using_hash_mmu() that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-1-mpe@ellerman.id.au

tools/testing/selftests/powerpc/utils.c

@@ -318,7 +318,9 @@ int using_hash_mmu(bool *using_hash)
 
 	rc = 0;
 	while (fgets(line, sizeof(line), f) != NULL) {
-		if (strcmp(line, "MMU		: Hash\n") == 0) {
+		if (!strcmp(line, "MMU		: Hash\n") ||
+		    !strcmp(line, "platform	: Cell\n") ||
+		    !strcmp(line, "platform	: PowerMac\n")) {
 			*using_hash = true;
 			goto out;
 		}