bpf: lsm: Remove hook to bpf_task_storage_free

free_task() already calls bpf_task_storage_free(). It is not necessary
to call it again on security_task_free(). Remove the hook.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://patch.msgid.link/20241212075956.2614894-1-song@kernel.org