mwifiex: apply radar flag

When IEEE80211_CHAN_RADAR is set by cfg80211, passive scan must be
performed. In mwifiex,active scan is performed even though flag is
set from cfg80211. mwifiex_reg_apply_radar_flags() function added
in this patch correctly uses radar flag.

Signed-off-by: Karthik Ananthapadmanabha <karthida@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>