drm/xe/rtp: Add "always true" match function

drm/xe/rtp: Add "always true" match function

All RTP table entries are required to have at least one rule.  In cases
where an entry should apply unconditionally across all platforms we've
been using a graphics version range of 12.00 - forever since this covers
all platforms supported by the driver.  However if the primary GT is
disabled via configfs (not actually possible today, but probably
possible in the future) or if we have a future platform that lacks a
primary GT and only supports media/display, this rule would cause
important programming to fail to apply on the media GT.

Add a simple match function that just always returns true
unconditionally.  This solves the worries above while also being more
immediately human-readable.

Reviewed-by: Shuicheng Lin <shuicheng.lin@intel.com>
Link: https://patch.msgid.link/20260424-engine-setup-v2-2-59cc620a25f1@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>