bcm63xx: reorganize board patches into fewer files

bcm63xx: reorganize board patches into fewer files

At the moment, bcm63xx creates one patch for each board to add to
board_bcm963xx.c. While this is not really helpful to get an overview
in the first place, it is particularly painful if you want to change
something for an early file and have to refresh all the later patches
accordingly.

Since it does not look like these board patches are upstreamed either,
this commit consolidates all board additions into one patch per "board".
By this, both adding and editing boards should become much simpler,
and we drop about 1300 lines of "code" from patches as well.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>