scsi: sd: reduce log level for suspend/resume log messages

Generally driver should be silent during the normal operation of the device
hence this change reduces the logs level for suspend/resume messages from
KERN_NOTICE to KERN_DEBUG.

Change-Id: I154fb7c759aa35ed32ea451729083c93fc385c11
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>