vio-vscsi: vscsi-report-luns can return 0
vio-vscsi: vscsi-report-luns can return 0

In case when vscsi-report-luns returns 0, the loop would go on
for 64K times before realising. Fixing this bug.

Signed-off-by: Nikunj A Dadhania <e2f4a5db9b4735182a88051d1e7a3599f9eac9db@linux.vnet.ibm.com>

agraf/SLOF,open-power-host-os/slof,agraf/SLOF,agraf/SLOF,stefanberger/SLOF-tpm,dgibson/SLOF,dgibson/SLOF,mdroth/SLOF,aik/SLOF,k0da/SLOF,agraf/SLOF,aik/SLOF,leilihh/SLOF,stefanberger/SLOF-tpm,leilihh/SLOF,aik/SLOF,open-power-host-os/slof,mdroth/SLOF,open-power-host-os/slof,dgibson/SLOF,k0da/SLOF,qemu/SLOF,open-power-host-os/slof,mdroth/SLOF,qemu/SLOF,mdroth/SLOF,stefanberger/SLOF-tpm,qemu/SLOF,leilihh/SLOF,k0da/SLOF,dgibson/SLOF,k0da/SLOF,leilihh/SLOF