Disable persistent net generator on Bookworm

Disable persistent net generator on Bookworm

This schema doesn't work. Even if the udev rule is there, the name of
the different NIC are different from one boot to the next. On a
machine (sabro*) with 3 different NIC, the name of each interface is
basically random and could take on of three name, "eth[0-2]".

net.ifnames=0 does still mean that we have "eth*" names, but the
generated file "75-persistent-net-generator" doesn't seems to name the
interfaces as expected.

The new predictable network interface names schema seems to work well
enough. The names are still the same after rebooting into Xen, at
least on the few machine tested so far. But, we will change to a "mac"
name policy in a follow-up commit.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>