staging: vchiq_debugfs: Use forward declarations

Use forward declarations for struct vchiq_state and vchiq_instance.
We can then drop the vchiq_core.h header from vchiq_debugfs.h.

Signed-off-by: Umang Jain <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.h

···
 #ifndef VCHIQ_DEBUGFS_H
 #define VCHIQ_DEBUGFS_H
 
-#include "vchiq_core.h"
+struct vchiq_state;
+struct vchiq_instance;
 
 struct vchiq_debugfs_node {
 	struct dentry *dentry;