isdn: fix NUL (\0 or \x00) specification in string

In C one can either use '\0' or '\x00' (or '\000') to add a NUL byte to
a string. '\0x00' isn't part of these and will in fact result in a
single NUL followed by "x00". This fixes that.
Signed-off-by: NGiel van Schijndel <me@mortis.eu>
Reported-at: http://www.viva64.com/en/b/0299/Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/hardware/eicon/message.c

@@ -4880,7 +4880,7 @@ static void sig_ind(PLCI *plci)
 	byte SS_Ind[] = "\x05\x02\x00\x02\x00\x00"; /* Hold_Ind struct*/
 	byte CF_Ind[] = "\x09\x02\x00\x06\x00\x00\x00\x00\x00\x00";
 	byte Interr_Err_Ind[] = "\x0a\x02\x00\x07\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-	byte CONF_Ind[] = "\x09\x16\x00\x06\x00\x00\0x00\0x00\0x00\0x00";
+	byte CONF_Ind[] = "\x09\x16\x00\x06\x00\x00\x00\x00\x00\x00";
 	byte force_mt_info = false;
 	byte dir;
 	dword d;