selftests: drv: net: avoid skipping tests

selftests: drv: net: avoid skipping tests

On a system with either of the ipv4 or ipv6 information missing, tests
are currently skipped. Ideally, the test should run as long as at least
one address family is present. This patch make test run whenever
possible.

Before:
./drivers/net/ping.py
TAP version 13
1..6
ok 1 ping.test_default # SKIP Test requires IPv4 connectivity
ok 2 ping.test_xdp_generic_sb # SKIP Test requires IPv4 connectivity
ok 3 ping.test_xdp_generic_mb # SKIP Test requires IPv4 connectivity
ok 4 ping.test_xdp_native_sb # SKIP Test requires IPv4 connectivity
ok 5 ping.test_xdp_native_mb # SKIP Test requires IPv4 connectivity
ok 6 ping.test_xdp_offload # SKIP device does not support offloaded XDP
Totals: pass:0 fail:0 xfail:0 xpass:0 skip:6 error:0

After:
./drivers/net/ping.py
TAP version 13
1..6
ok 1 ping.test_default
ok 2 ping.test_xdp_generic_sb
ok 3 ping.test_xdp_generic_mb
ok 4 ping.test_xdp_native_sb
ok 5 ping.test_xdp_native_mb
ok 6 ping.test_xdp_offload # SKIP device does not support offloaded XDP
Totals: pass:5 fail:0 xfail:0 xpass:0 skip:1 error:0

Fixes: 75cc19c8ff89 ("selftests: drv-net: add xdp cases for ping.py")
Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Link: https://patch.msgid.link/20250503013518.1722913-3-mohsin.bashr@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>