serial_txx9: cleanup includes

Do not include some header files already indluded by serial_core.h.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/serial_txx9.c

@@ -25,15 +25,11 @@
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/console.h>
-#include <linux/sysrq.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/pci.h>
-#include <linux/tty.h>
-#include <linux/tty_flip.h>
 #include <linux/serial_core.h>
 #include <linux/serial.h>
-#include <linux/mutex.h>
 
 #include <asm/io.h>