TTY/ASoC: Rename N_AMSDELTA line discipline to N_V253

The patch changes the line discipline name registered in include/linux/tty.h
and updates the ams-delta machine driver to use it.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 26af981..15bd3b0 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -47,7 +47,7 @@
 #define N_SLCAN		17	/* Serial / USB serial CAN Adaptors */
 #define N_PPS		18	/* Pulse per Second */
 
-#define N_AMSDELTA	19	/* codec control over modem, board specific */
+#define N_V253		19	/* Codec control over voice modem */
 
 /*
  * This character is the same as _POSIX_VDISABLE: it cannot be used as