mwifiex: use SYNC flag for canceling host sleep

Host sleep is cancelled in sdio resume() handler.
Cfg80211's resume handler is immediately called after
this. SYNC flag here ensures that host sleep handshake
gets completed and we have valid "adapter->nd_config"
before we report host wakeup reason in cfg80211's
resume handler.

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