kmod-setup: don't load unix.ko as a module anymore

Building unix.ko as a module always has been a really bad idea, from day
1. Debian used to do this, but has long been fixed. Kernel developers
saw the light too, and removed support for it in 6.5
(97154bcf4d1b7cabefec8a72cff5fbb91d5afb7b). Let's hence drop support for
this here too, and delete some old cruft. AF_UNIX is simply our most
basic IPC system and supporting systems without it being around is just
not realistic.

src/core/kmod-setup.c

@@ -112,9 +112,6 @@ int kmod_setup(void) {
                  * we try to configure ::1 on the loopback device. */
                 { "ipv6",                       "/sys/module/ipv6",          false, true,  NULL               },
 
-                /* This should never be a module */
-                { "unix",                       "/proc/net/unix",            true,  true,  NULL               },
-
                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
                 { "virtio_rng",                 NULL,                        false, false, has_virtio_rng     },