global: Move remaining CONFIG_SYS_NS16550_* to CFG_SYS_NS16550_*

The rest of the unmigrated CONFIG symbols in the CONFIG_SYS_NS16550
namespace do not easily transition to Kconfig. In many cases they likely
should come from the device tree instead. Move these out of CONFIG
namespace and in to CFG namespace.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/ci20.h b/include/configs/ci20.h
index 63dac1d..b7511ad 100644
--- a/include/configs/ci20.h
+++ b/include/configs/ci20.h
@@ -15,7 +15,7 @@
 #define CONFIG_SYS_INIT_SP_OFFSET	0x400000
 
 /* NS16550-ish UARTs */
-#define CONFIG_SYS_NS16550_CLK		48000000
+#define CFG_SYS_NS16550_CLK		48000000
 
 /* Ethernet: davicom DM9000 */
 #define CONFIG_DM9000_BASE		0xb6000000