block/scsi: correctly emulate the VPD block limits page

block/scsi: correctly emulate the VPD block limits page

When the device doesn't support the VPD block limits page, we emulate it even
for SCSI passthrough.

As a part of the emulation we need to add it to the 'Supported VPD Pages'

The code that does this adds it to the page, but it doesn't increase the length
of the data to be copied to the guest, thus the guest never sees the VPD block
limits page as supported.

Bump the transfer size by 1 in this case.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201217165612.942849-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>