In Arch Linux
mkinitcpio -p linux
shows
Possibly missing firmware for module: aic94xx
Possibly missing firmware for module: wd719x
git clone https://aur.archlinux.org/aic94xx-firmware.git
cd aic94xx-firmware
makepkg -sri
git clone https://aur.archlinux.org/wd719x-firmware.git
cd wd719x-firmware
makepkg -sri
and then mkinitcpio -p linux
again.
I suspect a lot of needless concern here stems from people conflating warnings and errors when they are distinct things. With a warning, consider if it applies and if not (as it won't for most people here in this case) or if you're not sure but have no specific observed problems, the simply carry on.