scsi: scsi_ioctl: Remove scsi_verify_blk_ioctl()

Manually verify that the device is not a partition and the caller has admin
privіleges at the beginning of the sr ioctl method and open code the
trivial check for sd as well.

Link: https://lore.kernel.org/r/20210724072033.1284840-11-hch@lst.de


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