drivers/ieee802154: Switch CC2520 to new net_ptk allocator
drivers/ieee802154: Switch CC2520 to new net_ptk allocator

Now buffer is allocated at the same time.

Signed-off-by: Tomasz Bursztyka <ba81a3a719836727e6857ae83462b9f52ec41006@linux.intel.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,ldts/zephyr,nashif/zephyr,ldts/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,nashif/zephyr