Move MTD mounts into fstab & split new fstab files for recovery

The mount_all builtin doesn't support mtd name to block device
mapping, so we need to specify the static block device for mounts
for the regular fstab. However, the recovery fstab needs to use
the mtd partition name to work correctly, so split the fstab into
separate files.

Change-Id: Ic0681e0ef91488fddb15355fc52bd58a90b0fb11