net: dhcpv4: Detect network interface on/off events
net: dhcpv4: Detect network interface on/off events

Catch interface up/down events so that we can renew the
address if interface goes down and is then restored.

Fixes #7553

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

finikorg/zephyr,finikorg/zephyr,kraj/zephyr,galak/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,mbolivar/zephyr,ldts/zephyr,finikorg/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,punitvara/zephyr,mbolivar/zephyr,zephyriot/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,mbolivar/zephyr,zephyriot/zephyr,Vudentz/zephyr,mbolivar/zephyr,finikorg/zephyr,Vudentz/zephyr,explora26/zephyr,kraj/zephyr,kraj/zephyr,ldts/zephyr,explora26/zephyr,nashif/zephyr,punitvara/zephyr,galak/zephyr,ldts/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,punitvara/zephyr,explora26/zephyr,Vudentz/zephyr,galak/zephyr,punitvara/zephyr,zephyriot/zephyr,zephyriot/zephyr,zephyriot/zephyr,ldts/zephyr,nashif/zephyr,explora26/zephyr,kraj/zephyr