sparc64: sunvdc: skip vdisk response validation upon error

sparc64: sunvdc: skip vdisk response validation upon error

Skip validating the vdisk IO response from vdisk server, if IO
request has failed.

sunvdc checks if the size of the request processed by the
server matches with the size of request sent by vdc. This
is to ensure that partial IO completions are caught, since
it's not expected. In the case where the server reports an
error, it could set the size of IO processed to zero.
Therefore, validating the size of request processed in the
case of an error could mis-classify the problem.

Orabug: 26242270

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>