Swithches IEEE 802.15.4 based code to using byte arrays instead of uint16_t values for short address and PAN ID

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Swithches IEEE 802.15.4 based code to using byte arrays instead of uint16_t values for short address and PAN ID

IEEE 802.15.4 Network Driver:  Add logic to setup the network mask, update the MAC-based IPv6 addressing when the network is brought up.  The idea is that addressing changes are supposed to occur only while the network is down but won't take effect until the network is up again.

ieee 802.15.4:  Need counting protection on the logic that releases the notification resources.  Otherwise, notification handlers may be operating with a stale pointer.

IEEE 802.15.4 MAC: Add list management and prioritization logic that will permit the MAC layer to support bound multiple clients.

stm32_hrtim

Approved-by: Gregory Nutt <gnutt@nuttx.org>

wireless/ieee802154: Renames Kconfig option, adds option for unimplemented receiver priority.

Approved-by: Gregory Nutt <gnutt@nuttx.org>

rfc6775: Fix header, add references, correct naming.  This is NOT ICMPv6, but part of 6LoWPAN that acts like ICMPv6.

stm32_hrtim

Approved-by: Gregory Nutt <gnutt@nuttx.org>

wireless/ieee802154: Minor improvements and simplified logic

Approved-by: Gregory Nutt <gnutt@nuttx.org>

ieee802.15.4 loopback:  Better simulation addressing: sort, extended, panid, and IP address conversion