drm/i915/skl: drop workarounds for A0 and B0 revisions

Pre-production hardware is not supported.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/7929af62a68504c84038a8db1625bd96ebaa9e6f.1474034059.git.jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 39417b7..47f7afa 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -269,8 +269,7 @@
 	struct drm_i915_private *dev_priv = engine->i915;
 
 	engine->disable_lite_restore_wa =
-		(IS_SKL_REVID(dev_priv, 0, SKL_REVID_B0) ||
-		 IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1)) &&
+		IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1) &&
 		(engine->id == VCS || engine->id == VCS2);
 
 	engine->ctx_desc_template = GEN8_CTX_VALID;
@@ -1068,9 +1067,8 @@
 {
 	uint32_t index = wa_ctx_start(wa_ctx, *offset, CACHELINE_DWORDS);
 
-	/* WaSetDisablePixMaskCammingAndRhwoInCommonSliceChicken:skl,bxt */
-	if (IS_SKL_REVID(engine->i915, 0, SKL_REVID_B0) ||
-	    IS_BXT_REVID(engine->i915, 0, BXT_REVID_A1)) {
+	/* WaSetDisablePixMaskCammingAndRhwoInCommonSliceChicken:bxt */
+	if (IS_BXT_REVID(engine->i915, 0, BXT_REVID_A1)) {
 		wa_ctx_emit(batch, index, MI_LOAD_REGISTER_IMM(1));
 		wa_ctx_emit_reg(batch, index, GEN9_SLICE_COMMON_ECO_CHICKEN0);
 		wa_ctx_emit(batch, index,