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/iNet_3F_defconfig b/configs/iNet_3F_defconfig
index 3f1624c..4969411 100644
--- a/configs/iNet_3F_defconfig
+++ b/configs/iNet_3F_defconfig
@@ -18,4 +18,5 @@
 # CONFIG_CMD_FLASH is not set
 # CONFIG_CMD_FPGA is not set
 CONFIG_CMD_GPIO=y
+CONFIG_SYS_NS16550=y
 CONFIG_USB_MUSB_HOST=y