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/ax25-ae350.h b/include/configs/ax25-ae350.h
index 7224bd8..e3b6956 100644
--- a/include/configs/ax25-ae350.h
+++ b/include/configs/ax25-ae350.h
@@ -33,7 +33,7 @@
 /*
  * Serial console configuration
  */
-#define CONFIG_SYS_NS16550_CLK		19660800
+#define CFG_SYS_NS16550_CLK		19660800
 
 /* Init Stack Pointer */