samples/bpf: fix symbol mismatch by compiler optimization

samples/bpf: fix symbol mismatch by compiler optimization

Currently, multiple kprobe programs are suffering from symbol mismatch
due to compiler optimization. These optimizations might induce
additional suffix to the symbol name such as '.isra' or '.constprop'.

    # egrep ' finish_task_switch| __netif_receive_skb_core' /proc/kallsyms
    ffffffff81135e50 t finish_task_switch.isra.0
    ffffffff81dd36d0 t __netif_receive_skb_core.constprop.0
    ffffffff8205cc0e t finish_task_switch.isra.0.cold
    ffffffff820b1aba t __netif_receive_skb_core.constprop.0.cold

To avoid this, this commit replaces the original kprobe section to
kprobe.multi in order to match symbol with wildcard characters. Here,
asterisk is used for avoiding symbol mismatch.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-5-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>