vga_switcheroo: fix build with non switcheroo enabled path.

Signed-off-by: Dave Airlie <airlied@redhat.com>

include/linux/vga_switcheroo.h

@@ -49,6 +49,7 @@ int vga_switcheroo_process_delayed_switch(void);
 static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
 static inline int vga_switcheroo_register_client(struct pci_dev *dev,
 					  void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state),
+					  void (*reprobe)(struct pci_dev *dev),
 					  bool (*can_switch)(struct pci_dev *dev)) { return 0; }
 static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
 static inline int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { return 0; }