tty/serial: lay the foundations for the next set of reworks

- Stop drivers calling their own flush method indirectly, it obfuscates code
  and it will change soon anyway

- A few more lock_kernel paths temporarily needed in some driver internal
  waiting code

- Remove private put_char method that does a write call for one char - we
  have that anyway

- Most but not yet all of the termios copy under lock fixing (some has other
  dependencies to follow)

- Note a few locking bugs in drivers found in the process

- Kill remaining [ab]users of TIOCG/SSOFTCAR in the driver, these must go to
  fix the termios locking

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

drivers/serial/netx-serial.c

@@ -287,6 +287,7 @@ static void netx_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	unsigned int val;
 
+	/* FIXME: Locking needed ? */
 	if (mctrl & TIOCM_RTS) {
 		val = readl(port->membase + UART_RTS_CR);
 		writel(val | RTS_CR_RTS, port->membase + UART_RTS_CR);