USB: musb: fix compilation warning in host only mode

Fixes below compilation warning when host only configuration is
selected.
drivers/usb/musb/musb_core.c: In function 'musb_stage0_irq':
drivers/usb/musb/musb_core.c:711: warning: unused variable 'mbase'
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Acked-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_core.c

@@ -704,7 +704,6 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 #ifdef CONFIG_USB_MUSB_HDRC_HCD
 	if (int_usb & MUSB_INTR_CONNECT) {
 		struct usb_hcd *hcd = musb_to_hcd(musb);
-		void __iomem *mbase = musb->mregs;
 
 		handled = IRQ_HANDLED;
 		musb->is_active = 1;
@@ -717,9 +716,9 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 		if (is_peripheral_active(musb)) {
 			/* REVISIT HNP; just force disconnect */
 		}
-		musb_writew(mbase, MUSB_INTRTXE, musb->epmask);
-		musb_writew(mbase, MUSB_INTRRXE, musb->epmask & 0xfffe);
-		musb_writeb(mbase, MUSB_INTRUSBE, 0xf7);
+		musb_writew(musb->mregs, MUSB_INTRTXE, musb->epmask);
+		musb_writew(musb->mregs, MUSB_INTRRXE, musb->epmask & 0xfffe);
+		musb_writeb(musb->mregs, MUSB_INTRUSBE, 0xf7);
 #endif
 		musb->port1_status &= ~(USB_PORT_STAT_LOW_SPEED
 					|USB_PORT_STAT_HIGH_SPEED