fix ts lint warning (#17049)

components/descriptions/index.tsx

@@ -10,12 +10,13 @@ import { ConfigConsumer, ConfigConsumerProps } from '../config-provider';
 
 export interface DescriptionsItemProps {
   prefixCls?: string;
-  label: React.ReactNode;
-  children: JSX.Element;
+  label?: React.ReactNode;
+  children: React.ReactNode;
   span?: number;
 }
 
-const DescriptionsItem: React.SFC<DescriptionsItemProps> = ({ children }) => children;
+const DescriptionsItem: React.SFC<DescriptionsItemProps> = ({ children }) =>
+  children as JSX.Element;
 
 export interface DescriptionsProps {
   prefixCls?: string;

components/descriptions/style/index.less

@@ -22,6 +22,7 @@
     border-radius: @border-radius-base;
     table {
       width: 100%;
+      table-layout: fixed;
     }
   }
 
@@ -90,6 +91,9 @@
   &.bordered {
     .@{descriptions-prefix-cls}-view {
       border: 1px solid @border-color-split;
+      > table {
+        table-layout: auto;
+      }
     }
     .@{descriptions-prefix-cls}-item-label,
     .@{descriptions-prefix-cls}-item-content {