tilapia: do some product cleanup
maguro: remove obsolete vold.fstab

This is now unified in fstab.tuna.
toro: remove obsolete vold.fstab

This is now unified in the base fstab.tuna file.
toroplus: remove obsolete vold.fstab

This file is no longer present, since it has been unified
in fstab.tuna.