scsi: refactor scsi_reset_provider handling

Pull the common code from the two callers into the function,
and rename it to scsi_ioctl_reset.

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