mwifiex: check for NL80211_SCAN_FLAG_RANDOM_ADDR during hidden SSID scan

At the end of user scan request, driver will perform an active
scan for hidden SSIDs in passive channels. While doing this,
driver unconditionally adding random_mac in scan command, which
is no expected. It should add random_mac only if scan_request
has NL80211_SCAN_FLAG_RANDOM_ADDR flag set.

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