mwifiex: resolve suspend() race with async FW init failure

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>