OvmfPkg/LsiScsiDxe: Install stubbed EXT_SCSI_PASS_THRU

OvmfPkg/LsiScsiDxe: Install stubbed EXT_SCSI_PASS_THRU

Partially implement LsiScsiControllerStart() and LsiScsiControllerStop()
to insert the scaffolding of EXT_SCSI_PASS_THRU functions.

v3: Squash the newline below the declaration of LSI_SCSI_FROM_PASS_THRU
v2: Remove the closing of PciIo protocol from LsiScsiControllerStop().

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200717061130.8881-6-glin@suse.com>