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/P5020DS_SPIFLASH_defconfig b/configs/P5020DS_SPIFLASH_defconfig
index 65cc600..cf8f5f0 100644
--- a/configs/P5020DS_SPIFLASH_defconfig
+++ b/configs/P5020DS_SPIFLASH_defconfig
@@ -5,3 +5,4 @@
 CONFIG_SPI_FLASH=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
+CONFIG_SYS_NS16550=y