drivers/usb/musb/musb_hcd.c: Fix GCC 4.6 warning

Fix:
musb_hcd.c: In function 'submit_control_msg':
musb_hcd.c:851:6: warning: variable 'csr' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Anatolij Gustschin <agust@denx.de>

drivers/usb/musb/musb_hcd.c

@@ -848,7 +848,6 @@ int submit_control_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
 			int len, struct devrequest *setup)
 {
 	int devnum = usb_pipedevice(pipe);
-	u16 csr;
 	u8  devspeed;
 
 #ifdef MUSB_NO_MULTIPOINT
@@ -862,7 +861,7 @@ int submit_control_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
 
 	/* select control endpoint */
 	writeb(MUSB_CONTROL_EP, &musbr->index);
-	csr = readw(&musbr->txcsr);
+	readw(&musbr->txcsr);
 
 #ifndef MUSB_NO_MULTIPOINT
 	/* target addr and (for multipoint) hub addr/port */