mwifiex: fix issue in resumed scan operation

When delayed scan operation is resumed, we just add next scan
command in queue but don't wakeup main thread to process the
command. Hence the command is downloaded to firmware only after
waking up the main thread by any other means.

This bug which was introduced after "mwifiex: improve scan delay
logic.." patch is fixed here.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>