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.
There should at least be an option in mkinitcpio to ignore specific firmware warnings... That way, the first time a user sees the warning, they can search the Arch Wiki and then once they know they don't need that firmware, they can change mkinitcpio.conf to suppress those specific warnings.