uwb: add the WiMedia LLC Protocol stack

Add the generic code for the WiMedia Logical Link Control Protocol (WLP).

This has been split into several patches for easier review.

core (this patch):
  - everything else

messages:
  - WLP message construction/decode

wss:
  - Wireless Service Set support

build-system:
  - Kconfig and Kbuild files

Signed-off-by: David Vrabel <david.vrabel@csr.com>