[media] nxt200x: increase write buffer size

The buffer size on nxt200x is not enough:

	...
	> Dec 20 10:52:04 rich kernel: [   31.747949] nxt200x: nxt200x_writebytes: i2c wr reg=002c: len=255 is too big!
	...

Increase it to 256 bytes.
Reported-by: Rich Freeman <rich0@gentoo.org>
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/dvb-frontends/nxt200x.c

@@ -40,7 +40,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 /* Max transfer size done by I2C transfer functions */
-#define MAX_XFER_SIZE  64
+#define MAX_XFER_SIZE  256
 
 #define NXT2002_DEFAULT_FIRMWARE "dvb-fe-nxt2002.fw"
 #define NXT2004_DEFAULT_FIRMWARE "dvb-fe-nxt2004.fw"