vfs_btrfs: Also call vfs_offload_token_ctx_init() in btrfs_offload_write_send()

vfs_btrfs: Also call vfs_offload_token_ctx_init() in btrfs_offload_write_send()

If a client for whatever reason calls FSCTL_SRV_COPYCHUNK[_WRITE] without
FSCTL_SRV_REQUEST_RESUME_KEY, we call btrfs_offload_write_send
before btrfs_offload_read_send.

This is similar to 462b74da79c51f9ba6dbd24e603aa904485d5123

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15758

Signed-off-by: Andreas Schneider <asn@samba.org>
Autobuild-User(v4-21-test): Jule Anger <janger@samba.org>
Autobuild-Date(v4-21-test): Tue Dec  3 18:04:26 UTC 2024 on atb-devel-224