target/s390x: Mark STFLE_53 facility as available

This facility bit includes load-on-condition-2 and
load-and-zero-rightmost-byte.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

target/s390x/cpu_models.c

@@ -687,6 +687,7 @@ static void add_qemu_cpu_model_features(S390FeatBitmap fbm)
         S390_FEAT_EXECUTE_EXT,
         S390_FEAT_FLOATING_POINT_SUPPPORT_ENH,
         S390_FEAT_STFLE_45,
+        S390_FEAT_STFLE_53,
     };
     int i;