REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3889 Currently the HTTP DNS Retry Interval is 2 second and no retry attempt. If DNS response can't arrive in 2 second, the DNS request is failed, and then HTTP boot is failed. In order to resolve this issue, Add PCDs to support RetryCount and RetryInterval configured in Platform. Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com> Cc: Fu Siyuan <siyuan.fu@intel.com> Cc: Wu Jiaxin <jiaxin.wu@intel.com> Signed-off-by: Heng Luo <heng.luo@intel.com> Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>