s390/topology: remove sysinfo header include, add forward declaration instead

Any change to sysinfo.h causes a whole kernel recompile since sysinfo.h is
included by topology.h, which again is used nearly everywhere.
So remove that include and add a forward declaration instead.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/topology.h

@@ -2,8 +2,8 @@
 #define _ASM_S390_TOPOLOGY_H
 
 #include <linux/cpumask.h>
-#include <asm/sysinfo.h>
 
+struct sysinfo_15_1_x;
 struct cpu;
 
 #ifdef CONFIG_SCHED_BOOK

arch/s390/kernel/topology.c

@@ -17,6 +17,7 @@
 #include <linux/cpu.h>
 #include <linux/smp.h>
 #include <linux/mm.h>
+#include <asm/sysinfo.h>
 
 #define PTF_HORIZONTAL	(0UL)
 #define PTF_VERTICAL	(1UL)