x86/shadow: Deviate multi.h as being included multiple times

Use a SAF-8 marker.

This addresses a MISRA D4.10 violation.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

xen/arch/x86/mm/shadow/multi.h

@@ -8,6 +8,7 @@
  * Parts based on earlier work by Michael A Fetterman, Ian Pratt et al.
  */
 
+/* SAF-8-safe inclusion procedure left to caller */
 extern int
 SHADOW_INTERNAL_NAME(sh_map_and_validate_gl1e, GUEST_LEVELS)(
     struct vcpu *v, mfn_t gl1mfn, void *new_gl1p, u32 size);