usb/storage: redefine US_BULK_FLAG_IN and use it

US_BULK_FLAG_IN is defined as 1 and not used. The USB storage spec says
that bit 7 of flags within CBW defines the data direction. 1 is DATA-IN
(read from device) and 0 is the DATA-OUT. Bit 6 is obselete and bits 0-5
are reserved.
This patch redefines the unsued define US_BULK_FLAG_IN from 1 to 1 << 7
aka 0x80 and replaces the obvious users. In a following patch the
storage gadget will use it as well.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/storage/transport.c

@@ -1071,7 +1071,8 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
 	/* set up the command wrapper */
 	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 	bcb->DataTransferLength = cpu_to_le32(transfer_length);
-	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
+	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ?
+		US_BULK_FLAG_IN : 0;
 	bcb->Tag = ++us->tag;
 	bcb->Lun = srb->device->lun;
 	if (us->fflags & US_FL_SCM_MULT_TARG)