Call for testers: migrating to TI's DTS files

[Oleksandr Tymoshenko]

Hello,

I’ve just finished last stage of rewriting FreeBSD TI support so
it can use TI's upstream DTS files. It makes much easier to use
various DTS overlays for BBB shields. e.g. I managed to get 
4DCAPE-43 working with drop-in dtb file generated from [1]
and some manual gpio pin manipulations. 

In order to maintain compatiblity (as much as it's possible) with
existing setups we still use files in sys/boot/fdt/dts but they are
wrappers around TI's DTS files in sys/gnu/ with some FreeBSD glue,
namely:

- PRUSS device node for beaglebone*.dts
- Additional pandaboard-es.dts file for Pandaboard ES
- global timer node for OMAP4 (Pandaboard). It is required for 
    event timer. 
- /chosen node with uart2 as stdin/stdout for OMAP4 (Pandaboard)
- FreeBSD-specific "non-removable" flag for mmc1 on OMAP4
- Disable mmc5 on OMAP4 which seems to have some problems with clock setup

The most disruptive change is that now each GPIO bank is addresses
individually so when you access pin directly using gpioctl,
intead of using /dev/gpioc0 and pin number 55, you should use 
/dev/gpioc1 and pin 23 (each bank is 32 pins)

I'd appreciate if you tested it with your setups. I tested it on
Beaglebone Black and Pandaboard ES and it worked for me (c)

Patch: https://people.freebsd.org/~gonzo/arm/patches/ti-fdt-20150404.diff
Review: https://reviews.freebsd.org/D2146

[1] https://github.com/RobertCNelson/dtb-linux-dev/blob/master/src/arm/am335x-boneblack-4dcape-70t.dts