ath: dfs_pattern_detector: Fix some function kernel-doc headers

ath: dfs_pattern_detector: Fix some function kernel-doc headers

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/ath/dfs_pattern_detector.c:34: warning: Function parameter or member 'region' not described in 'radar_types'
 drivers/net/wireless/ath/dfs_pattern_detector.c:141: warning: Function parameter or member 'region' not described in 'get_dfs_domain_radar_types'
 drivers/net/wireless/ath/dfs_pattern_detector.c:239: warning: Function parameter or member 'dpd' not described in 'channel_detector_get'
 drivers/net/wireless/ath/dfs_pattern_detector.c:239: warning: Function parameter or member 'freq' not described in 'channel_detector_get'

Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201102112410.1049272-22-lee.jones@linaro.org