ns16550: move CONFIG_SYS_NS16550 to Kconfig

Move CONFIG_SYS_NS16550 to Kconfig, and run moveconfig.py.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
diff --git a/configs/tuxx1_defconfig b/configs/tuxx1_defconfig
index c8db21a..7675fb3 100644
--- a/configs/tuxx1_defconfig
+++ b/configs/tuxx1_defconfig
@@ -2,3 +2,4 @@
 CONFIG_MPC83xx=y
 CONFIG_TARGET_TUXX1=y
 CONFIG_SYS_EXTRA_OPTIONS="TUXX1"
+CONFIG_SYS_NS16550=y