bpf: Save memory alloction info in bpf_local_storage

bpf: Save memory alloction info in bpf_local_storage

Save the memory allocation method used for bpf_local_storage in the
struct explicitly so that we don't need to go through the hassle to
find out the info. When a later patch replaces BPF memory allocator
with kmalloc_noloc(), bpf_local_storage_free() will no longer need
smap->storage_ma to return the memory and completely remove the
dependency on smap in bpf_local_storage_free().

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-4-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>