s390/sclp: unify basic sclp access by exposing "struct sclp"

Let's unify basic access to sclp fields by storing the data in an external
struct in asm/sclp.h.

The values can now directly be accessed by other components, so there is
no need for most accessor functions and external variables anymore.

The mtid, mtid_max and facility part will be cleaned up separately.

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 80875c4..76e8737 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -213,7 +213,7 @@
 	 * Make sure the memory block size is always greater
 	 * or equal than the memory increment size.
 	 */
-	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp_get_rzm());
+	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE