selftests/bpf: move test_lirc_mode2_user to TEST_GEN_PROGS_EXTENDED

test_lirc_mode2_user is included in test_lirc_mode2.sh test and should
not be run directly.

Fixes: 6bdd533c

 ("bpf: add selftest for lirc_mode2 type program")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>