Ubuntu 14.04 Install Firmare released for ath10k_pci

First of all, you have installed an official linux-firmware package from an official Ubuntu repository. But you installed a version for Ubuntu 15.10.

It did not install automatically, because the Atheros new firmware is available only for Ubuntu 15.10 (wily) at the moment.

Version numbers for linux-firmware for different Ubuntu releases differ. That is why this firmware package will never be replaced by anything in Ubuntu 14.04.

But I do not see any reason to worry about that.

If you really want to bother about that, you can track if that new Atheros firmware gets into Ubuntu 14.04 linux-firmware package and when it does (if ever) you can remove that package and install a native one for 14.04.

But I can't imagine why that may be ever needed.

Since you installed from an Ubuntu deb file you don't have to do anything. When Ubuntu finds a newer version of linux-firmware it will be installed when you do updates