drm/i915/adlp: Fix GEM VM asserts for DPT VMs

An object mapped via DPT can have remapped and rotated VMA instances
besides the normal VMA instance, similarly to GGTT VMA instances.
Adjust the corresponding VMA lookup asserts.

While at it also check if a DPT VM is passed incorrectly to
i915_vm_to_ppgtt().

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210524172703.2113058-2-imre.deak@intel.com