[media] atmel-isc: Fix the static checker warning

Initialize the pointer 'fmt' before the start of
the loop.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Songjun Wu <songjun.wu@microchip.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/atmel/atmel-isc.c

@@ -1490,6 +1490,7 @@ static int isc_formats_init(struct isc_device *isc)
 		}
 	}
 
+	fmt = &isc_formats[0];
 	for (i = 0, num_fmts = 0; i < ARRAY_SIZE(isc_formats); i++) {
 		if (fmt->isc_support || fmt->sd_support)
 			num_fmts++;