mwifiex: don't pretend to resume while remove()'ing

The device core will not allow suspend() to race with remove().

Signed-off-by: Brian Norris <briannorris@chromium.org>
Tested-by: Xinming Hu <huxm@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>