drm/i915: have *_debugfs_init() functions return void.

Since commit 987d65d01356 (drm: debugfs: make
drm_debugfs_create_files() never fail), drm_debugfs_create_files() never
fails and should return void. Therefore, remove its use as the
return value of debugfs_init() functions and have the functions return
void.

v2: convert intel_display_debugfs_register() stub to return void too.

Signed-off-by: Wambui Karuga <[e-mail]>
Reviewed-by: Jani Nikula <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/display/intel_display_debugfs.c

···
 	{"i915_edp_psr_debug", &i915_edp_psr_debug_fops},
 };
 
-int intel_display_debugfs_register(struct drm_i915_private *i915)
+void intel_display_debugfs_register(struct drm_i915_private *i915)
 {
 	struct drm_minor *minor = i915->drm.primary;
 	int i;
···
 				    intel_display_debugfs_files[i].fops);
 	}
 
-	return drm_debugfs_create_files(intel_display_debugfs_list,
-					ARRAY_SIZE(intel_display_debugfs_list),
-					minor->debugfs_root, minor);
+	drm_debugfs_create_files(intel_display_debugfs_list,
+				 ARRAY_SIZE(intel_display_debugfs_list),
+				 minor->debugfs_root, minor);
 }
 
 static int i915_panel_show(struct seq_file *m, void *data)

drivers/gpu/drm/i915/display/intel_display_debugfs.h

···
 struct drm_i915_private;
 
 #ifdef CONFIG_DEBUG_FS
-int intel_display_debugfs_register(struct drm_i915_private *i915);
+void intel_display_debugfs_register(struct drm_i915_private *i915);
 int intel_connector_debugfs_add(struct drm_connector *connector);
 #else
-static inline int intel_display_debugfs_register(struct drm_i915_private *i915) { return 0; }
+static inline void intel_display_debugfs_register(struct drm_i915_private *i915) {}
 static inline int intel_connector_debugfs_add(struct drm_connector *connector) { return 0; }
 #endif
 

drivers/gpu/drm/i915/i915_debugfs.c

···
 	{"i915_guc_log_relay", &i915_guc_log_relay_fops},
 };
 
-int i915_debugfs_register(struct drm_i915_private *dev_priv)
+void i915_debugfs_register(struct drm_i915_private *dev_priv)
 {
 	struct drm_minor *minor = dev_priv->drm.primary;
 	int i;
···
 				    i915_debugfs_files[i].fops);
 	}
 
-	return drm_debugfs_create_files(i915_debugfs_list,
-					I915_DEBUGFS_ENTRIES,
-					minor->debugfs_root, minor);
+	drm_debugfs_create_files(i915_debugfs_list,
+				 I915_DEBUGFS_ENTRIES,
+				 minor->debugfs_root, minor);
 }

drivers/gpu/drm/i915/i915_debugfs.h

···
 struct seq_file;
 
 #ifdef CONFIG_DEBUG_FS
-int i915_debugfs_register(struct drm_i915_private *dev_priv);
+void i915_debugfs_register(struct drm_i915_private *dev_priv);
 void i915_debugfs_describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj);
 #else
-static inline int i915_debugfs_register(struct drm_i915_private *dev_priv) { return 0; }
+static inline void i915_debugfs_register(struct drm_i915_private *dev_priv) {}
 static inline void i915_debugfs_describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj) {}
 #endif