radeon_hd: Fix app_server bt regression introduced at hrev46862

* We adjusted the array of pointers to be larger, but
  didn't adjust the malloc to be larger.
* Should solve #10563 and maybe #10536
ARM: Name beagleboneblk back to beagle

* Pulkomandy pointed out that all Beagle hardware is
  very similar so we could likely get away with a single
  ARM target board.