serial_txx9: cleanup includes

Do not include some header files already indluded by serial_core.h.

Signed-off-by: Atsushi Nemoto <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Acked-by: Alan Cox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/serial/serial_txx9.c

···
 #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>