ns16550: unify serial_ppc

Unify serial_ppc, and use the generic binding.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Add TODO comment]
Signed-off-by: Tom Rini <trini@konsulko.com>
4 files changed