net: ethernet: mvneta: Fix napi structure mixup on armada 3700

The mvneta Ethernet driver is used on a few different Marvell SoCs.
Some SoCs have per cpu interrupts for Ethernet events. Some SoCs have
a single interrupt, independent of the CPU. The driver handles this by
having a per CPU napi structure when there are per CPU interrupts, and
a global napi structure when there is a single interrupt.

When the napi core calls mvneta_poll(), it passes the napi
instance. This was not being propagated through the call chain, and
instead the per-cpu napi instance was passed to napi_gro_receive()
call. This breaks when there is a single global napi instance.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Fixes: 2636ac3c ("net: mvneta: Add network support for Armada 3700 SoC")
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>