tty.h: remove dead define

No longer used. TTY_FLIPBUF_SIZE will also go soon but needs a couple of
other cleanups first

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/tty.h

@@ -80,11 +80,6 @@ struct tty_bufhead {
 	struct tty_buffer *free;	/* Free queue head */
 	int memory_used;		/* Buffer space used excluding free queue */
 };
-/*
- * The pty uses char_buf and flag_buf as a contiguous buffer
- */
-#define PTY_BUF_SIZE	4*TTY_FLIPBUF_SIZE
-
 /*
  * When a break, frame error, or parity error happens, these codes are
  * stuffed into the flags buffer.