[media] omap3isp: fix compiler warning

This patch fixes this compiler warning:
  drivers/media/video/omap3isp/isp.c: In function 'isp_isr_dbg':
  drivers/media/video/omap3isp/isp.c:392:2: warning: zero-length
   gnu_printf format string
Signed-off-by: Sanjeev Premi <premi@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/omap3isp/isp.c

@@ -391,7 +391,7 @@ static inline void isp_isr_dbg(struct isp_device *isp, u32 irqstatus)
 	};
 	int i;
 
-	dev_dbg(isp->dev, "");
+	dev_dbg(isp->dev, "ISP IRQ: ");
 
 	for (i = 0; i < ARRAY_SIZE(name); i++) {
 		if ((1 << i) & irqstatus)