It didn't cause big issues when VT-d was disabled.
But in VT-d enabled platform, lack of EhcFreeUrb call caused
the DMA data was not moved back to user's buffer.
It caused the correct data cannot be got through sync interrupt
transfer.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>