ath10k: print htt op_version upon driver boot

HTT version itself isn't sufficient to know what
HTT version given firmware blob uses. Hence print
the recently introduced HTT op version code.

While at it make the info string a bit more
consistent and clear.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>