drm/xe: Convert pre-GMDID IPs to struct xe_ip

drm/xe: Convert pre-GMDID IPs to struct xe_ip

We have now a struct xe_ip to fully describe an IP, but we are only
using that for GMDID-based IPs.

For pre-GMDID IPs, we still describe release info (version and name) via
feature descriptors (struct xe_{graphics,media}_desc). Let's convert
those to use struct xe_ip.

With this, we have a uniform way of describing IPs in the xe driver
instead of having different approaches based on whether the IPs use
GMDIDs or not.

A nice side-effect of this change is that now we have an easy way to
lookup, in the source code, mappings between versions, names and
features for all supported IPs.

v2:
  - Store pointers to struct xe_ip instead xe_{graphics,media}_desc in
    struct xe_device_desc.

Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250221-xe-unify-ip-descriptors-v2-5-5bc0c6d0c13f@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>