cnss2: Check device power state for Suspend / Resume operations

If WLAN driver probe fails, its intenal state may not be
proper. Thus check for device powered on state before calling
WLAN driver operations for suspend / resume.

Change-Id: I81da8969e9b0e0525256db8da2c0db25a996b241
Signed-off-by: Manikandan Mohan <manikand@codeaurora.org>