ath10k: remove multiple defines of DIAG_TRANSFER_LIMIT

DIAG_TRANSFER_LIMIT is redefined with same value and comments
just below this entry, remove this duplicate entry.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>