MdeModulePkg/.../IdeMode: correctly report length of returned data

MdeModulePkg/.../IdeMode: correctly report length of returned data

For some SCSI commands, notably INQUIRY, it's relatively common for
the device to provide less data than we intended to read, and for
this reason EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET makes
InTransferLength and OutTransferLength read-write.  Make ATAPI
aware of this.

This makes it possible to handle EFI_NOT_READY always, not just
for read as done in r19685.

I've chosen to use a break statement instead of calling
CheckStatusRegister directly; the break statement reaches a
pre-existing call the CheckStatusRegister function.  This
ensures that the assignment to *ByteCount is not missed, and
adds a further sanity check to DRQClear.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19737 6f19259b-4bc3-4df7-8a09-765794883524