perf bpf: Fix map data leak in bpf_metadata_create() on alloc failure

perf bpf: Fix map data leak in bpf_metadata_create() on alloc failure

bpf_metadata_create() calls bpf_metadata_read_map_data() which
allocates map.btf and map.rodata.  If the subsequent
bpf_metadata_alloc() fails, the code does 'continue' which skips
bpf_metadata_free_map_data(), permanently leaking both allocations.

Fix by calling bpf_metadata_free_map_data() before continue.

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: ab38e84ba9a80581 ("perf record: collect BPF metadata from existing BPF programs")
Cc: Blake Jones <blakejones@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>