x86/shim: annotate for Misra C:2012 rule 20.12

... ("A macro parameter used as an operand to the `#' or `##' operators,
which is itself subject to further macro replacement, shall only be used
as an operand to these operators"). Leverage the SAF-6 annotation we have
available.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Nicola Vetrini <nicola.vetrini@bugseng.com>

xen/arch/x86/pv/shim.c

@@ -124,8 +124,10 @@ void __init pv_shim_fixup_e820(void)
     ASSERT(i < ARRAY_SIZE(reserved_pages));     \
     reserved_pages[i++].mfn = pfn;              \
 })
+    /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
     MARK_PARAM_RAM(HVM_PARAM_STORE_PFN);
     if ( !pv_console )
+        /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
         MARK_PARAM_RAM(HVM_PARAM_CONSOLE_PFN);
 #undef MARK_PARAM_RAM
 }
@@ -207,10 +209,14 @@ void __init pv_shim_setup_dom(struct domain *d, l4_pgentry_t *l4start,
         evtchn_reserve(d, param);                                              \
     }                                                                          \
 })
+    /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
     SET_AND_MAP_PARAM(HVM_PARAM_STORE_PFN, si->store_mfn, store_va);
+    /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
     SET_AND_MAP_PARAM(HVM_PARAM_STORE_EVTCHN, si->store_evtchn, 0);
+    /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
     SET_AND_MAP_PARAM(HVM_PARAM_CONSOLE_EVTCHN, si->console.domU.evtchn, 0);
     if ( !pv_console )
+        /* SAF-6-safe Rule 20.12 expansion of macros HVM_PARAM_*. */
         SET_AND_MAP_PARAM(HVM_PARAM_CONSOLE_PFN, si->console.domU.mfn,
                           console_va);
 #undef SET_AND_MAP_PARAM