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/firefly-rk3288_defconfig b/configs/firefly-rk3288_defconfig
index 6f42377..196e6e2 100644
--- a/configs/firefly-rk3288_defconfig
+++ b/configs/firefly-rk3288_defconfig
@@ -38,6 +38,7 @@
 CONFIG_DEBUG_UART_BASE=0xff690000
 CONFIG_DEBUG_UART_CLOCK=24000000
 CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
 CONFIG_USE_PRIVATE_LIBGCC=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_ERRNO_STR=y