8250: allow platforms to override PM hook.

Add a hook for platforms to specify custom pm methods.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 7638dea..bf9c2bd 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -35,6 +35,8 @@
 	void		(*set_termios)(struct uart_port *,
 			               struct ktermios *new,
 			               struct ktermios *old);
+	void		(*pm)(struct uart_port *, unsigned int state,
+			      unsigned old);
 };
 
 /*
@@ -76,5 +78,7 @@
 extern int setup_early_serial8250_console(char *cmdline);
 extern void serial8250_do_set_termios(struct uart_port *port,
 		struct ktermios *termios, struct ktermios *old);
+extern void serial8250_do_pm(struct uart_port *port, unsigned int state,
+			     unsigned int oldstate);
 
 #endif