net: ipv4: Drop incoming packets with src addr is multicast
net: ipv4: Drop incoming packets with src addr is multicast

As per RFC1112 sec 6.2 "A host group address must never be
placed in the source address field or anywhere in a source
route or record route option of an outgoing IP datagram."

Signed-off-by: Ravi kumar Veeramally <406c082aeb452858c41b213a757768e1c1dff29e@linux.intel.com>

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