[S390] Add processor type march=z10 and a processor type safety check.

This patch adds the code generation option for IBM System z10 and
adds a check in head[31,64].S to prevents the execution of a kernel
compiled for a new processor type on an old machine.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index e6efc12..7a18d23 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -230,6 +230,14 @@
 	  Class (z9 BC). The kernel will be slightly faster but will not
 	  work on older machines such as the z990, z890, z900, and z800.
 
+config MARCH_Z10
+	bool "IBM System z10"
+	help
+	  Select this to enable optimizations for IBM System z10. The
+	  kernel will be slightly faster but will not work on older
+	  machines such as the z990, z890, z900, z800, z9-109, z9-ec
+	  and z9-bc.
+
 endchoice
 
 config PACK_STACK