drm/i915/step: s/<platform>_revid_tbl/<platform>_revids

Simplify the stepping info array name.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210713193635.3390052-2-matthew.d.roper@intel.com