host/broadcom: create new package, move bcm283x and videocore under it

For the record, I'm still ambivalent if this passes the bar of pain/long term benefit. Header wise, beagle was done this way from the start. On the other hand rpi merges everything as one package.

Jan 14 '19 19:01 maruel

I think I won't after all.

Sep 20 '23 18:09 maruel