libertas_tf: if_usb.c: don't export static symbol

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
type T;
identifier f;
@@

static T f (...) { ... }

@@
identifier r.f;
declarer name EXPORT_SYMBOL_GPL;
@@

-EXPORT_SYMBOL_GPL(f);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/libertas_tf/if_usb.c

@@ -365,7 +365,6 @@ static int if_usb_reset_device(struct if_usb_card *cardp)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(if_usb_reset_device);
 
 /**
  *  usb_tx_block - transfer data to the device
@@ -907,7 +906,6 @@ restart:
 	lbtf_deb_leave_args(LBTF_DEB_USB, "ret %d", ret);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(if_usb_prog_firmware);
 
 
 #define if_usb_suspend NULL