HID: bpf: add hid_get/put_device() helpers

no code change, but this way we reduce code duplication and we
can export it later.

Link: https://lore.kernel.org/r/20240608-hid_bpf_struct_ops-v3-2-6ac6ade58329@kernel.org


Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>