ath10k: print service ready returned channel range

Displays lowest/highest supported channels for both 2ghz and 5ghz
bands as they're fetched within WMI service ready event.
These are shown in a frequency format.

Signed-off-by: Tomislav Požega <pozega.tomislav@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>