MdePkg:Add a new error status code EFI_HTTP_ERROR.

MdePkg:Add a new error status code EFI_HTTP_ERROR.

v2:
*Return the EFI_HTTP_ERROR in the “Status” field in token, instead of
in the status codes returned table of EFI_HTTP_PROTOCOL.Response() interface.

Add a new error status code EFI_HTTP_ERROR in corresponding with
the UEFI 2.6 spec

Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Siyuan Fu <siyuan.fu@intel.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>