staging: fsl-dpaa2/eth: Initialize variable before use

In dpni_get_irq_status(), status is both in and out parameter,
so initialize before use.
Issue found through static analysis tool.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>