sample: bpf: syscall_tp_user: Print result of verify_map

sample: bpf: syscall_tp_user: Print result of verify_map

At the end of the test, we already print out
    prog <prog number>: map ids <...> <...>
Value is the number read from kernel through bpf map, further print out
    verify map:<map id> val:<...>
will help users to understand the program runs successfully.

Signed-off-by: Song Chen <chensong_2000@189.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648889828-12417-1-git-send-email-chensong_2000@189.cn