drivers/usb/host/ehci-mxc.c: Fix GCC 4.6 warning

Fix:
ehci-mxc.c: In function 'ehci_hcd_init':
ehci-mxc.c:113:6: warning: variable 'tmp' set but not used
[-Wunused-but-set-variable]
Signed-off-by: NAnatolij Gustschin <agust@denx.de>

drivers/usb/host/ehci-mxc.c

@@ -110,11 +110,10 @@ int ehci_hcd_init(void)
 {
 	struct usb_ehci *ehci;
 #ifdef CONFIG_MX31
-	u32 tmp;
 	struct clock_control_regs *sc_regs =
 		(struct clock_control_regs *)CCM_BASE;
 
-	tmp = __raw_readl(&sc_regs->ccmr);
+	__raw_readl(&sc_regs->ccmr);
 	__raw_writel(__raw_readl(&sc_regs->ccmr) | (1 << 9), &sc_regs->ccmr) ;
 #endif