net: sh_eth: Fix receive packet "exceeded" condition in sh_eth_rx()

This patch fixes the packet "exceeded" condition in sh_eth_rx() when
RACT in an RX descriptor is not set and the "quota" is 0.
Otherwise, kernel panic happens because the "&n->poll_list" is deleted
twice in sh_eth_poll() which calls napi_complete() and net_rx_action().

Signed-off-by: Kouei Abe <kouei.abe.cp@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>