ttusb-dec: treat firmware data as const

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/media/dvb/ttusb-dec/ttusb_dec.c

@@ -1275,7 +1275,7 @@ static int ttusb_dec_boot_dsp(struct ttusb_dec *dec)
 	u8 b1[] = { 0x61 };
 	u8 *b;
 	char idstring[21];
-	u8 *firmware = NULL;
+	const u8 *firmware = NULL;
 	size_t firmware_size = 0;
 	u16 firmware_csum = 0;
 	__be16 firmware_csum_ns;