[SCSI] Revert "[SCSI] Retrieve the Caching mode page"

This reverts commit 24d720b7

.

Previously we thought there was little possibility that devices would
crash with this, but some have been found.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>