x86/HVM: address Misra 2.1 rule violations

In hvm_set_cr3() the "bad_cr3" label is reachable only with
SHADOW_PAGING=y; the code being there is therefore a Misra rule 2.1
(unreachable code) violation when SHADOW_PAGING=n.

Similarly code past the initial switch() in hvm_debug_op() is reachable
only when CONFIG_INTEL_VMX=y.

No functional change.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger@xenproject.org>

xen/arch/x86/hvm/hvm.c

@@ -2455,6 +2455,7 @@ int hvm_set_cr3(unsigned long value, bool noflush, bool may_defer)
     return X86EMUL_OKAY;
 
  bad_cr3:
+    BUILD_ERROR_IF_NOT(CONFIG_SHADOW_PAGING);
     gdprintk(XENLOG_ERR, "Invalid CR3\n");
     domain_crash(currd);
     return X86EMUL_UNHANDLEABLE;
@@ -5201,6 +5202,8 @@ int hvm_debug_op(struct vcpu *v, int32_t op)
             return -ENOSYS;
     }
 
+    BUILD_ERROR_IF_NOT(CONFIG_INTEL_VMX);
+
     vcpu_pause(v);
 
     switch ( op )