OvmfPkg/MptScsiDxe: Implement the PassThru method

OvmfPkg/MptScsiDxe: Implement the PassThru method

Machines should be able to boot after this commit. Tested with different
Linux distributions (Ubuntu, CentOS) and different Windows
versions (Windows 7, Windows 10, Server 2016).

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2390
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200504210607.144434-12-nikita.leshchenko@oracle.com>
[lersek@redhat.com: MPT_SCSI_DMA_ADDR_HIGH: drop redundant space char]