s390/cio: wait_cons_dev don't use static variable

wait_cons_dev is used to busy wait for an interrupt on the console
ccw device. Stop using the static console_subchannel and add a
parameter to this function to specify on which ccw device/subchannel
we have to do the polling.

While at it rename the function to ccw_device_wait_idle and
move it to device.c

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 4a1ff5c..3b97c8b 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -133,6 +133,7 @@
 extern struct subchannel *cio_get_console_subchannel(void);
 extern spinlock_t * cio_get_console_lock(void);
 extern void *cio_get_console_priv(void);
+extern void cio_tsch(struct subchannel *sch);
 #else
 #define cio_is_console(schid) 0
 #define cio_get_console_subchannel() NULL