bpf: test: fix spelling mistake "REUSEEPORT" -> "REUSEPORT"

Trivial fix to spelling mistake in error message

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>