[PATCH] powerpc: Add the ability to handle SOC ports in legacy_serial

Add the ability to configure and initialize legacy 8250 serials
ports on an SOC bus.  Also, fixed an issue that we would not
configure any serial ports if "linux,stdout-path" was not found.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>