VM: fix corruption from recursive PDE allocation
VM: fix corruption from recursive PDE allocation

Change-Id: I6176b849fefca4bed3e92648b0d72ff47658915c

veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi