misra: add deviation for headers that explicitly avoid guards

Some headers, under specific circumstances (documented in a comment at
the beginning of the file), explicitly do not have strict inclusion
guards: the caller is responsible for including them correctly.

These files are not supposed to comply with Directive 4.10:
"Precautions shall be taken in order to prevent the contents of a header
file being included more than once"

This patch adds deviation cooments for headers that avoid guards.

Signed-off-by: Simone Ballarin <simone.ballarin@bugseng.com>
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

docs/misra/safe.json

@@ -68,6 +68,14 @@
         },
         {
             "id": "SAF-8-safe",
+            "analyser": {
+                "eclair": "MC3R1.D4.10"
+            },
+            "name": "Dir 4.10: headers that leave it up to the caller to include them correctly",
+            "text": "Headers that deliberatively leave the responsability of their correct inclusion to the caller are allowed."
+        },
+        {
+            "id": "SAF-9-safe",
             "analyser": {},
             "name": "Sentinel",
             "text": "Next ID to be used"

xen/include/public/arch-x86/cpufeatureset.h

@@ -23,6 +23,7 @@
  * their XEN_CPUFEATURE() being appropriate in the included context.
  */
 
+/* SAF-8-safe inclusion procedure left to caller */
 #ifndef XEN_CPUFEATURE
 
 /*

xen/include/public/errno.h

@@ -17,6 +17,7 @@
  * will unilaterally #undef XEN_ERRNO().
  */
 
+/* SAF-8-safe inclusion procedure left to caller */
 #ifndef XEN_ERRNO
 
 /*