ARC: HAPS: cleanup defconfigs from unused ETH drivers

We have multiple vendors ethernet drivers enabled in haps_hs and
haps_hs_smp defconfig. The only one we possibly require is
VIRTIO_NET. So disable unused ones via disabling entire
CONFIG_ETHERNET which controls all vendor-specific ethernet
drivers.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>