ath10k: handle pdev_chan_info wmi event

Add handler to process bss channel information wmi event that
will be received upon sending pdev_chan_info_request wmi command.

Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>