drm/i915/debugfs: add dedicated intel_display_caps debugfs for display

Add dedicated intel_display_caps for display, with device info and
params. Intentionally prefix the file intel_ instead of i915_. Going
forward, we should do the same for all debugfs files, making them
independent of i915 and xe.

Remove display param dumping from i915 specific i915_capabilities
debugfs.

Note that we don't add node_to_intel_display() functionality in
to_intel_display(). It's too specific for that.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1b825b893dd2d423da167a7b6b21d05e8cd0182c.1726231866.git.jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>