net: veth: Disable netpoll support

net: veth: Disable netpoll support

The current implementation of netpoll in veth devices leads to
suboptimal behavior, as it triggers warnings due to the invocation of
__netif_rx() within a softirq context. This is not compliant with
expected practices, as __netif_rx() has the following statement:

	lockdep_assert_once(hardirq_count() | softirq_count());

Given that veth devices typically do not benefit from the
functionalities provided by netpoll, Disable netpoll for veth
interfaces.

Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20240805094012.1843247-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>