drm/xe/display: remove intel_display_step_name() to simplify

drm/xe/display: remove intel_display_step_name() to simplify

The intel_display_step_name() is an unnecessary extra
indirection. Simplify by just adding a macro to map intel_step_name() to
xe_step_name().

We'll need to temporarily add a compat INTEL_DISPLAY_STEP() for this.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cbea7def331cc9d2438da49ae344b9987f27cd12.1724180287.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>