Multiple unrelated changes

- replace the hand written serial input flush routine with the termios one.
- serialport_discard_read isn't necessary anymore - it just wrapped
  sp_flush_incoming with no extra value.
- serialport_read and serialport_write would misbehave if read or write
  didn't process everything in one go.
- sp_flush_incoming should be #define'd out for FAKE_COMMUNICATION like
  serialport_discard_read was

Corresponding to flashrom svn r831.

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>
Acked-by: Sean Nelson <audiohacked@gmail.com>

flash.h

@@ -598,7 +598,6 @@ extern int sp_fd;
 int serialport_shutdown(void);
 int serialport_write(unsigned char *buf, unsigned int writecnt);
 int serialport_read(unsigned char *buf, unsigned int readcnt);
-int serialport_discard_read(void);
 
 #include "chipdrivers.h"