thp, s390: architecture backend for thp on s390

This implements the architecture backend for transparent hugepages
on s390.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 7f47176..00d1144 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -388,6 +388,8 @@
 		S390_lowcore.machine_flags |= MACHINE_FLAG_SPP;
 	if (test_facility(50) && test_facility(73))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_TE;
+	if (test_facility(66))
+		S390_lowcore.machine_flags |= MACHINE_FLAG_RRBM;
 #endif
 }