drm/i915/jsl_ehl: Use revid->stepping tables

Switch JSL/EHL to use a revid->stepping table as we're trying to do on
all platforms going forward.

v2:
 - Use COMMON_STEP().  (Anusha)

Bspec: 29153
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210713193635.3390052-9-matthew.d.roper@intel.com