drm/i915/kbl: Drop pre-production revision from stepping table

We're long past the point where we need to care about pre-production
hardware, and we already warn the user and taint the kernel if we detect
the driver is being loaded on pre-production hardware.

Bspec: 18329
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/20210713193635.3390052-5-matthew.d.roper@intel.com

drivers/gpu/drm/i915/intel_step.c

@@ -33,7 +33,6 @@ static const struct intel_step_info skl_revids[] = {
 };
 
 static const struct intel_step_info kbl_revids[] = {
-	[0] = { .gt_step = STEP_A0, .display_step = STEP_A0 },
 	[1] = { .gt_step = STEP_B0, .display_step = STEP_B0 },
 	[2] = { .gt_step = STEP_C0, .display_step = STEP_B0 },
 	[3] = { .gt_step = STEP_D0, .display_step = STEP_B0 },