ieee802154: enforce consistent endianness in the 802.15.4 stack

Enable sparse warnings about endianness, replace the remaining fields
regarding network operations without explicit endianness annotations
with such that are annotated, and propagate this through the entire
stack.

Uses of ieee802154_addr_sa are not changed yet, this patch is only
concerned with all other fields (such as address filters, operation
parameters and the likes).

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>