sd: fix up ->compat_ioctl

No need to verify the passthrough ioctls, the real handler will
take care of that.  Also make sure not to block for resets on
O_NONBLOCK fds.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>