selftests: drv-net: Test XDP_PASS/DROP support

selftests: drv-net: Test XDP_PASS/DROP support

Test XDP_PASS/DROP in single buffer and multi buffer mode when
XDP native support is available.

./drivers/net/xdp.py
TAP version 13
1..4
ok 1 xdp.test_xdp_native_pass_sb
ok 2 xdp.test_xdp_native_pass_mb
ok 3 xdp.test_xdp_native_drop_sb
ok 4 xdp.test_xdp_native_drop_mb
\# Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Link: https://patch.msgid.link/20250719083059.3209169-3-mohsin.bashr@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>