net: pkt: Add flag indicating if pkt has already been processed by L2
net: pkt: Add flag indicating if pkt has already been processed by L2

Add a new flag, indicating if packet has already been processed by L2 or
not. This can be used with AF_PACKET sockets, to select a proper socket
type for currently processed packet.

Signed-off-by: Robert Lubos <9d28997c6894a2d0321a7bb399169af7ce99b64e@nordicsemi.no>

zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr