btrfs: tests: fix chunk map leak after failure to add it to the tree

commit 009ca358 upstream.

If we fail to add the chunk map to the fs mapping tree we exit
test_rmap_block() without freeing the chunk map. Fix this by adding a
call to btrfs_free_chunk_map() before exiting the test function if the
call to btrfs_add_chunk_map() failed.

Fixes: 7dc66abb ("btrfs: use a dedicated data structure for chunk maps")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>