net/context: No need to set pkt family as the allocator did already
net/context: No need to set pkt family as the allocator did already

net_context uses net_pkt_alloc_with_buffer(), which sets the family and
protocol (according to parameters) so no need to set the family again.

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

nashif/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,nashif/zephyr,finikorg/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,explora26/zephyr,Vudentz/zephyr,galak/zephyr,explora26/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,galak/zephyr,finikorg/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,ldts/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,Vudentz/zephyr