bpf: lsm: Set bpf_lsm_blob_sizes.lbs_task to 0

bpf: lsm: Set bpf_lsm_blob_sizes.lbs_task to 0

bpf task local storage is now using task_struct->bpf_storage, so
bpf_lsm_blob_sizes.lbs_task is no longer needed. Remove it to save some
memory.

Fixes: a10787e6d58c ("bpf: Enable task local storage for tracing programs")
Cc: stable@vger.kernel.org
Cc: KP Singh <kpsingh@kernel.org>
Cc: Matt Bobrowski <mattbobrowski@google.com>
Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20240911055508.9588-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>