ttydev: fix pamc_zilog for tty pointer move

Today's linux-next build (sparc64 defconfig) failed like this:

drivers/serial/sunhv.c: In function `receive_chars':
drivers/serial/sunhv.c:188: error: structure has no member named `tty'
drivers/serial/sunsu.c: In function `receive_chars':
drivers/serial/sunsu.c:314: error: structure has no member named `tty'
drivers/serial/sunsab.c: In function `receive_chars':
drivers/serial/sunsab.c:121: error: structure has no member named `tty'

I applied the following patch (which, again, may not be correct).

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/serial/sunsu.c b/drivers/serial/sunsu.c
index 1074e73..e24e682 100644
--- a/drivers/serial/sunsu.c
+++ b/drivers/serial/sunsu.c
@@ -311,7 +311,7 @@
 static struct tty_struct *
 receive_chars(struct uart_sunsu_port *up, unsigned char *status)
 {
-	struct tty_struct *tty = up->port.info->tty;
+	struct tty_struct *tty = up->port.info->port.tty;
 	unsigned char ch, flag;
 	int max_count = 256;
 	int saw_console_brk = 0;