selftests/bpf: Xsk selftests - adding xdpxceiver to .gitignore

This patch adds *xdpxceiver* to selftests/bpf/.gitignore

Reported-by: Yonghong Song <[e-mail]>
Suggested-by: Yonghong Song <[e-mail]>
Signed-off-by: Weqaar Janjua <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/testing/selftests/bpf/.gitignore

···
 /runqslower
 /bench
 *.ko
+xdpxceiver