drm/i915/gvt: Cleanup unwanted public symbols

drivers/gpu/drm/i915/gvt/execlist.c:531:6: warning: symbol 'clean_execlist' was not declared. Should it be static?
drivers/gpu/drm/i915/gvt/execlist.c:545:6: warning: symbol 'reset_execlist' was not declared. Should it be static?
drivers/gpu/drm/i915/gvt/execlist.c:556:5: warning: symbol 'init_execlist' was not declared. Should it be static?
drivers/gpu/drm/i915/gvt/scheduler.c:248:6: warning: symbol 'release_shadow_wa_ctx' was not declared. Should it be static?

References: 06bb372f ("drm/i915/gvt: Introduce intel_vgpu_reset_submission")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: intel-gvt-dev@lists.freedesktop.org
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/execlist.c

@@ -528,7 +528,7 @@ static void init_vgpu_execlist(struct intel_vgpu *vgpu, int ring_id)
 	vgpu_vreg(vgpu, ctx_status_ptr_reg) = ctx_status_ptr.dw;
 }
 
-void clean_execlist(struct intel_vgpu *vgpu)
+static void clean_execlist(struct intel_vgpu *vgpu)
 {
 	enum intel_engine_id i;
 	struct intel_engine_cs *engine;
@@ -542,7 +542,7 @@ void clean_execlist(struct intel_vgpu *vgpu)
 	}
 }
 
-void reset_execlist(struct intel_vgpu *vgpu,
+static void reset_execlist(struct intel_vgpu *vgpu,
 		unsigned long engine_mask)
 {
 	struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
@@ -553,7 +553,7 @@ void reset_execlist(struct intel_vgpu *vgpu,
 		init_vgpu_execlist(vgpu, engine->id);
 }
 
-int init_execlist(struct intel_vgpu *vgpu)
+static int init_execlist(struct intel_vgpu *vgpu)
 {
 	reset_execlist(vgpu, ALL_ENGINES);
 	return 0;

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -245,7 +245,7 @@ static int copy_workload_to_ring_buffer(struct intel_vgpu_workload *workload)
 	return 0;
 }
 
-void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
+static void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
 {
 	if (!wa_ctx->indirect_ctx.obj)
 		return;