cpu_x86: Simplify insertions into a linked list

The next pointer is initialized to NULL, overwriting to with another
NULL doesn't hurt.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/cpu/cpu_x86.c

@@ -563,12 +563,8 @@ x86VendorLoad(xmlXPathContextPtr ctxt,
     vendor->cpuid.edx = virReadBufInt32LE(string + 4);
     vendor->cpuid.ecx = virReadBufInt32LE(string + 8);
 
-    if (!map->vendors) {
-        map->vendors = vendor;
-    } else {
     vendor->next = map->vendors;
     map->vendors = vendor;
-    }
 
  cleanup:
     VIR_FREE(string);
@@ -768,12 +764,8 @@ x86FeatureLoad(xmlXPathContextPtr ctxt,
         map->migrate_blockers = migrate_blocker;
     }
 
-    if (!map->features) {
-        map->features = feature;
-    } else {
     feature->next = map->features;
     map->features = feature;
-    }
 
  cleanup:
     ctxt->node = ctxt_node;
@@ -1108,12 +1100,8 @@ x86ModelLoad(xmlXPathContextPtr ctxt,
             goto error;
     }
 
-    if (!map->models) {
-        map->models = model;
-    } else {
     model->next = map->models;
     map->models = model;
-    }
 
  cleanup:
     VIR_FREE(vendor);
@@ -1209,13 +1197,8 @@ x86MapLoadInternalFeatures(virCPUx86MapPtr map)
         if (virCPUx86DataAddCPUID(feature->data, &x86_kvm_features[i].cpuid))
             goto error;
 
-        if (!map->features) {
-            map->features = feature;
-        } else {
         feature->next = map->features;
         map->features = feature;
-        }
-
         feature = NULL;
     }