habanalabs: de-couple MMU and VM module initialization

This patch initializes the MMU S/W structures before the VM S/W
structures, instead of doing that as part of the VM S/W initialization.

This is done because we need to configure some MMU mappings for the kernel
context, before the VM is initialized. The VM initialization can't be
moved earlier because it depends on the size of the DRAM, which is
retrieved from the device CPU. Communication with the device CPU will
require the MMU mappings to be configured and hence the de-coupling.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>