Activate CONFIG_ATH9K_HWRNG in Kernel 4.9
Username: Tom Li
Origin: https://bugs.openwrt.org/index.php?do=details&task_id=1444
Since Linux 4.5, ath9k can be used as a random number generator using ADC register as a source of entropy. It is well-known that insufficient entropy is often a problem on routers and weakens security, using ath9k as a random number generator can greatly boost the available entropy on the routers without the need of additional measures such as haveged.