AR6003 2.1.1 supports both 1792 and 2048 byte board files.
Add support for 2048 byte board file.

kvalo: add ath6kl prefix to the title
Signed-off-by: NPrasanna Kumar <kumarpra@qca.qualcomm.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>