[yocto] [meta-raspberry] Raspberry Pi 3

[Trevor Woerner]

Thanks to everyone for their help!! It looks like I've got something working,
not sure if this is a "solution" or if most would just consider it a
work-around:

1) use Andrei's meta-raspberrypi layer (which selects linux kernel 4.1 by
default)

2) add the following to your local.conf:
	
	SERIAL_CONSOLE_forcevariable = "115200 ttyS0"
	CORE_FREQ = "250"

3) ??

4) profit!!

I've tested with poky building both core-image-x11 and
core-image-full-cmdline.

Best regards,
	Trevor