mwifiex: fix radar detection issue

It's been observed that firmware sends RADAR detected event without
specifying bss_num/bss_type. Also, the event body is empty.
Currently the event is being ignored by driver.

This patch checks on which interface 11H is active, accordingly fills
bss_num/bss_type and handles the event. Condition
"if (le32_to_cpu(rdr_event->passed))" which always fails is also removed.

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