ath10k: separate result parameter in ath10k_bmi_execute()

It's just cleaner to have separate argument for the parameter and result. Also
fix returned error value if response length is invalid.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: check otp.bin result

When we execute otp.bin in the target check that the result it returns doesn't
contain an error. This is to make sure that we don't accidentally use invalid
calibration data.

While at it, remove the useless label in the function and add few debug messages.

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