caif: remove unused struct member

The tty_name member of struct ser_device is never set or used, so it
can be removed. (The definition of struct ser_device is private to
this .c file, and the identifier tty_name only occurs in this one
place.)
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/caif/caif_serial.c

@@ -70,7 +70,6 @@ struct ser_device {
 	struct tty_struct *tty;
 	bool tx_started;
 	unsigned long state;
-	char *tty_name;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_tty_dir;
 	struct debugfs_blob_wrapper tx_blob;