drivers: slip: Add LLDP support
drivers: slip: Add LLDP support

Enable LLDP TX support on the slip ethernet driver.
Now when CONFIG_NET_LLDP is enabled, one can easily verify on a sniffer
(i.e. wireshark) that LLDP frames are being sent at the configured
interval with all mandatory TLVs enabled.

Signed-off-by: Jesus Sanchez-Palencia <1d20c8e4bc5d088c92fbf17f94216ea9e3f7ce5e@intel.com>

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