Disintegrate asm/system.h for Sparc

Disintegrate asm/system.h for Sparc.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: sparclinux@vger.kernel.org
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 7bb71b6..1e750e41 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -25,6 +25,7 @@
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>	/* flush_sig_insns */
+#include <asm/switch_to.h>
 
 #include "sigutil.h"