[media] lirc: Make struct file_operations pointer const

struct file_operations was made const in the drivers, but not in struct
lirc_driver:

drivers/staging/lirc/lirc_it87.c:365: warning: initialization discards qualifiers from pointer target type
drivers/staging/lirc/lirc_parallel.c:571: warning: initialization discards qualifiers from pointer target type
drivers/staging/lirc/lirc_serial.c:1073: warning: initialization discards qualifiers from pointer target type
drivers/staging/lirc/lirc_sir.c:482: warning: initialization discards qualifiers from pointer target type
drivers/staging/lirc/lirc_zilog.c:1284: warning: assignment discards qualifiers from pointer target type

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

include/media/lirc_dev.h

@@ -139,7 +139,7 @@ struct lirc_driver {
 	struct lirc_buffer *rbuf;
 	int (*set_use_inc) (void *data);
 	void (*set_use_dec) (void *data);
-	struct file_operations *fops;
+	const struct file_operations *fops;
 	struct device *dev;
 	struct module *owner;
 };