MdeModulePkg/Ip4Dxe: Correct the return status

MdeModulePkg/Ip4Dxe: Correct the return status

This patch made the following change:
* DataItem->Status should be updated to the status code.
* Data should not be freed if EFI_NOT_READY returned.

Cc: Santhapur Naveen <naveens@amiindia.co.in>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>