TTY: switch tty_flip_buffer_push

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/bfin_jtag_comm.c b/drivers/tty/bfin_jtag_comm.c
index 143c385..a93a424 100644
--- a/drivers/tty/bfin_jtag_comm.c
+++ b/drivers/tty/bfin_jtag_comm.c
@@ -95,18 +95,16 @@
 
 		/* if incoming data is ready, eat it */
 		if (bfin_read_DBGSTAT() & EMUDIF) {
-			if (tty != NULL) {
-				uint32_t emudat = bfin_read_emudat();
-				if (inbound_len == 0) {
-					pr_debug("incoming length: 0x%08x\n", emudat);
-					inbound_len = emudat;
-				} else {
-					size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
-					pr_debug("  incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
-					inbound_len -= num_chars;
-					tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars);
-					tty_flip_buffer_push(tty);
-				}
+			uint32_t emudat = bfin_read_emudat();
+			if (inbound_len == 0) {
+				pr_debug("incoming length: 0x%08x\n", emudat);
+				inbound_len = emudat;
+			} else {
+				size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
+				pr_debug("  incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
+				inbound_len -= num_chars;
+				tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars);
+				tty_flip_buffer_push(&port);
 			}
 		}