net: stats: Priority field was used instead of traffic class
net: stats: Priority field was used instead of traffic class

The network statistics is stored for each traffic class, but the
collecting function was given net_pkt priority. The priority
must be first converted to traffic class and then the statistics
stored to correct place in the stats array.

Signed-off-by: Jukka Rissanen <f9f077d1da4c7aa947f9864fa5a28c3588f6a45d@linux.intel.com>

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