drm/xe/uapi: Rename *_mem_regions masks

- 'native' doesn't make much sense on integrated devices.
- 'slow' is not necessarily true and doesn't go well with opposition
  to 'native'.

Instead, let's use 'near' vs 'far'. It makes sense with all the current
Intel GPUs and it is future proof. Right now, there's absolutely no need
to define among the 'far' memory, which ones are slower, either in terms
of latency, nunmber of hops or bandwidth.

In case of this might become a requirement in the future, a new query
could be added to indicate the certain 'distance' between a given engine
and a memory_region. But for now, this fulfill all of the current
requirements in the most straightforward way for the userspace drivers.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>