ath10k: deduplicate wmi_channel code

The structure is being set up in 2 places.
Deduplicate the code by creating a helper.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index d3e4502..51b16e1 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -1755,6 +1755,7 @@
 			ch->passive = passive;
 
 			ch->freq = channel->center_freq;
+			ch->band_center_freq1 = channel->center_freq;
 			ch->min_power = 0;
 			ch->max_power = channel->max_power * 2;
 			ch->max_reg_power = channel->max_reg_power * 2;