XSM: guard .sysctl() and .readconsole() hooks

Leaving the hook pointers in struct xsm_ops when !SYSCTL would lead to
the BUG_ON() in xsm_fixup_ops() triggering for respectively configured
hypervisors.

While moving the #ifdef for the corresponding xsm_*() wrappers, also move
those for xsm_page_offline() (where the hook pointer field already is
suitably guarded).

Fixes: c9eabaa03a ("xen/xsm: wrap around xsm_sysctl with CONFIG_SYSCTL")
Fixes: bddd9af604 ("xen/sysctl: wrap around XEN_SYSCTL_readconsole")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Release-Acked-by: Oleskii Kurochko <oleskii.kurochko@gmail.com>

xen/include/xsm/xsm.h

@@ -61,8 +61,10 @@ struct xsm_ops {
 #endif
     int (*set_target)(struct domain *d, struct domain *e);
     int (*domctl)(struct domain *d, struct xen_domctl *op);
+#ifdef CONFIG_SYSCTL
     int (*sysctl)(int cmd);
     int (*readconsole)(uint32_t clear);
+#endif
 
     int (*evtchn_unbound)(struct domain *d, struct evtchn *chn, domid_t id2);
     int (*evtchn_interdomain)(struct domain *d1, struct evtchn *chn1,
@@ -248,23 +250,17 @@ static inline int xsm_domctl(xsm_default_t def, struct domain *d,
     return alternative_call(xsm_ops.domctl, d, op);
 }
 
+#ifdef CONFIG_SYSCTL
 static inline int xsm_sysctl(xsm_default_t def, int cmd)
 {
-#ifdef CONFIG_SYSCTL
     return alternative_call(xsm_ops.sysctl, cmd);
-#else
-    return -EOPNOTSUPP;
-#endif
 }
 
 static inline int xsm_readconsole(xsm_default_t def, uint32_t clear)
 {
-#ifdef CONFIG_SYSCTL
     return alternative_call(xsm_ops.readconsole, clear);
-#else
-    return -EOPNOTSUPP;
-#endif
 }
+#endif
 
 static inline int xsm_evtchn_unbound(
     xsm_default_t def, struct domain *d1, struct evtchn *chn, domid_t id2)
@@ -558,14 +554,12 @@ static inline int xsm_resource_setup_misc(xsm_default_t def)
     return alternative_call(xsm_ops.resource_setup_misc);
 }
 
+#ifdef CONFIG_SYSCTL
 static inline int xsm_page_offline(xsm_default_t def, uint32_t cmd)
 {
-#ifdef CONFIG_SYSCTL
     return alternative_call(xsm_ops.page_offline, cmd);
-#else
-    return -EOPNOTSUPP;
-#endif
 }
+#endif
 
 static inline int xsm_hypfs_op(xsm_default_t def)
 {