Everything using standard isa I/O ports and IRQ windup is considerd
being an actual isa device.  That are all serial_init() users except
mips_mipssim() which seems to have a non-standard IRQ windup.

baud rate is fixed at 115200 now as no caller passed in something else.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>