tools/lguest: fix features_accepted logic in example launcher.

We were clearing the lower bits when setting the upper bits.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index 60cabaf..b3e73f2 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -1721,7 +1721,7 @@
 			d->features_accepted |= val;
 		} else {
 			assert(d->mmio->cfg.guest_feature_select == 1);
-			d->features_accepted &= ((u64)0xFFFFFFFF << 32);
+			d->features_accepted &= 0xFFFFFFFF;
 			d->features_accepted |= ((u64)val) << 32;
 		}
 		if (d->features_accepted & ~d->features)