ath10k: ignore configuring the incorrect board_id

With command to get board_id from otp, in the case of following

  boot get otp board id result 0x00000000 board_id 0 chip_id 0
  boot using board name 'bus=pci,bmi-chip-id=0,bmi-board-id=0"
  ...
  failed to fetch board data for bus=pci,bmi-chip-id=0,bmi-board-id=0 from
  ath10k/QCA6174/hw3.0/board-2.bin

The invalid board_id=0 will be used as index to search in the board-2.bin.

Ignore the case with board_id=0, as it means the otp is not carrying
the board id information.

Signed-off-by: Ryan Hsu <ryanhsu@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>