[media] cxusb: increase buffer length to 80 bytes

As reported by Vincent:
	[   16.332247] xc2028 0-0061: Loading firmware for type=BASE F8MHZ (3), id 0000000000000000.
	[   16.344378] cxusb: i2c wr: len=64 is too big!

64 bytes is too short for firmware load on this device. So, increase it
to 80 bytes.
Reported-by: NVincent McIntyre <vincent.mcintyre@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/usb/dvb-usb/cxusb.c

@@ -46,7 +46,7 @@
 #include "si2157.h"
 
 /* Max transfer size done by I2C transfer functions */
-#define MAX_XFER_SIZE  64
+#define MAX_XFER_SIZE  80
 
 /* debug */
 static int dvb_usb_cxusb_debug;