NetworkPkg/DnsDxe: cosmetic fixups

add whitespace according to coding style.

Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Signed-off-by: Wenyi Xie <xiewenyi2@huawei.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>

NetworkPkg/DnsDxe/DnsImpl.h

@@ -125,7 +125,7 @@ typedef struct {
   EFI_DNS6_COMPLETION_TOKEN  *Token;
 } DNS6_TOKEN_ENTRY;
 
-union _DNS_FLAGS{
+union _DNS_FLAGS {
   struct {
     UINT16     RCode:4;
     UINT16     Zero:3;