Disintegrate asm/system.h for PowerPC

Disintegrate asm/system.h for PowerPC.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: linuxppc-dev@lists.ozlabs.org

arch/powerpc/kvm/book3s_hv.c

@@ -45,6 +45,7 @@
 #include <asm/cputhreads.h>
 #include <asm/page.h>
 #include <asm/hvcall.h>
+#include <asm/switch_to.h>
 #include <linux/gfp.h>
 #include <linux/vmalloc.h>
 #include <linux/highmem.h>