staging: gdm72xx: Remove unnecessary extern declarations from header files

Fixes the following checkpatch.pl issue:

CHECK: extern prototypes should be avoided in .h files

Signed-off-by: Michalis Pappas <mpappas@fastmail.fm>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm72xx/gdm_wimax.h

@@ -64,8 +64,8 @@ struct nic {
 
 /*#define LOOPBACK_TEST */
 
-extern int register_wimax_device(struct phy_dev *phy_dev, struct device *pdev);
-extern int gdm_wimax_send_tx(struct sk_buff *skb, struct net_device *dev);
-extern void unregister_wimax_device(struct phy_dev *phy_dev);
+int register_wimax_device(struct phy_dev *phy_dev, struct device *pdev);
+int gdm_wimax_send_tx(struct sk_buff *skb, struct net_device *dev);
+void unregister_wimax_device(struct phy_dev *phy_dev);
 
 #endif

drivers/staging/gdm72xx/sdio_boot.h

@@ -16,6 +16,6 @@
 
 struct sdio_func;
 
-extern int sdio_boot(struct sdio_func *func);
+int sdio_boot(struct sdio_func *func);
 
 #endif /* __SDIO_BOOT_H__ */

drivers/staging/gdm72xx/usb_boot.h

@@ -16,7 +16,7 @@
 
 struct usb_device;
 
-extern int usb_boot(struct usb_device *usbdev, u16 pid);
-extern int usb_emergency(struct usb_device *usbdev);
+int usb_boot(struct usb_device *usbdev, u16 pid);
+int usb_emergency(struct usb_device *usbdev);
 
 #endif /* __USB_BOOT_H__ */