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>