[configs][arm64] Re-enable legacy PTYs

Change-Id: I718af3ecb0270849c7f20de4f823ffc9703a10bc
diff --git a/arch/arm64/configs/machina_defconfig b/arch/arm64/configs/machina_defconfig
index e6c75b6..2c8d845 100644
--- a/arch/arm64/configs/machina_defconfig
+++ b/arch/arm64/configs/machina_defconfig
@@ -13,7 +13,6 @@
 CONFIG_VIRTIO_BLK=y
 CONFIG_NETDEVICES=y
 CONFIG_VIRTIO_NET=y
-# CONFIG_LEGACY_PTYS is not set
 CONFIG_SERIAL_AMBA_PL011=y
 CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_VIRTIO_CONSOLE=y