drm/i915/guc/ct: Drop guards in enable/disable calls

We track the status of the GuC much more closely now and we expect the
enable/disable functions to be correctly called only once. If this isn't
true we do want to flag it as a flow failure (via the BUG_ON in the ctch
functions) and not silently ignore the call.
Suggested-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191217012316.13271-2-daniele.ceraolospurio@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c

@@ -862,9 +862,6 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
 	struct intel_guc *guc = ct_to_guc(ct);
 	struct intel_guc_ct_channel *ctch = &ct->host_channel;
 
-	if (ctch->enabled)
-		return 0;
-
 	return ctch_enable(guc, ctch);
 }
 
@@ -877,8 +874,5 @@ void intel_guc_ct_disable(struct intel_guc_ct *ct)
 	struct intel_guc *guc = ct_to_guc(ct);
 	struct intel_guc_ct_channel *ctch = &ct->host_channel;
 
-	if (!ctch->enabled)
-		return;
-
 	ctch_disable(guc, ctch);
 }