d/control: add Conflicts and Replaces for ath9k-htc firmware

d/control: add Conflicts and Replaces for ath9k-htc firmware

Reported in the community forum [0].

Both firmware files that are in the package [1]

> /lib/firmware/ath9k_htc/htc_7010-1.4.0.fw
> /lib/firmware/ath9k_htc/htc_9271-1.4.0.fw

seem to have been present since the linux-firmware submodule commit
3de1c437 ("Add v1.4.0 firmware for ath9k_htc.") which is present since
tag 20190717.

[0]: https://forum.proxmox.com/threads/135758/post-664862
[1]: https://packages.debian.org/bookworm/all/firmware-ath9k-htc/filelist

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>