Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callb...

Revert "scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()"

This reverts commit 8fef74658240abab2a2c5e3fd35a3d9c989e2196.

Dexuan reported a regression where StorVSC fails to probe a device (and
where, consequently, the VM may fail to boot).  The root-cause analysis led
to a long-standing race condition that is exposed by the validation /commit
in question.  Let's put the new validation aside until a proper solution
for that race condition is in place.

Link: https://lore.kernel.org/r/20201211131404.21359-1-parri.andrea@gmail.com
Fixes: 8fef74658240 ("scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()")
Cc: Dexuan Cui <decui@microsoft.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>