drm/drv: Remove initialization of static variables

Address the following checkpatch errors:
ERROR: do not initialise statics to false
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1613701811-32037-1-git-send-email-tiantao6@hisilicon.com

drivers/gpu/drm/drm_drv.c

@@ -61,7 +61,7 @@ static struct idr drm_minors_idr;
  * prefer to embed struct drm_device into their own device
  * structure and call drm_dev_init() themselves.
  */
-static bool drm_core_init_complete = false;
+static bool drm_core_init_complete;
 
 static struct dentry *drm_debugfs_root;