Getting the plcom serial port working as console on the RPI3?

[Brian Buhrow <buhrow%nfbcal.org@localhost>]

	hello.  I've been trying to get my RPI3 booting with -current for the
past week or so.  I was finally able to get it booted and running with a
7.99.55 kernel, but ifconfig didn't work with that kernel.  So, I thought
i'd try to attach a serial console, using the Adafruit TTL->USB adapter.
This combination of things works fine on my RPI model B, but on the RPI3, I
just get garbage on the terminal when I plug in the RPI3.   The linux
documentation says the com port on the RPI3 is different than it's been in
the past because of the addition of the bluetooth chip.  I tried adding the
following lines to cmdline.txt in /boot of the flash media to see if I can
get any sensiccal data out of the serial port:

enable_uart=1
core_freq=250

But these lines don't seem to help.

Any ideas?
-thanks
-Brian