s390/lowcore: replace lowcore irb array with a per-cpu variable

Remove the 96-byte irb array from the lowcore and create a per-cpu
variable instead. That way we will pick up any change in the definition
of the struct irb automatically.

Acked-By: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/cio.h

@@ -102,6 +102,8 @@ struct subchannel {
 	struct schib_config config;
 } __attribute__ ((aligned(8)));
 
+DECLARE_PER_CPU(struct irb, cio_irb);
+
 #define to_subchannel(n) container_of(n, struct subchannel, dev)
 
 extern int cio_validate_subchannel (struct subchannel *, struct subchannel_id);