atari_NCR5380: Refactor Falcon special cases

Make the atari_NCR5380.c core driver usable by sun3_scsi, mac_scsi and
others by moving some of the Falcon-specific code out of the core driver:
!IS_A_TT, atari_read_overruns and falcon_dont_release. Replace these with
hostdata variables and flags. FLAG_CHECK_LAST_BYTE_SENT is unused in
atari_NCR5380.c so don't set it.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/NCR5380.h

@@ -241,6 +241,7 @@
 #define FLAG_NCR53C400			4	/* NCR53c400 */
 #define FLAG_NO_PSEUDO_DMA		8	/* Inhibit DMA */
 #define FLAG_DTC3181E			16	/* DTC3181E */
+#define FLAG_LATE_DMA_SETUP		32	/* Setup NCR before DMA H/W */
 
 #ifndef ASM
 struct NCR5380_hostdata {
@@ -269,6 +270,9 @@ struct NCR5380_hostdata {
 	struct delayed_work coroutine;		/* our co-routine */
 	struct scsi_eh_save ses;
 	char info[256];
+	int read_overruns;                /* number of bytes to cut from a
+	                                   * transfer to handle chip overruns */
+	int retain_dma_intr;
 #ifdef PSEUDO_DMA
 	unsigned spin_max_r;
 	unsigned spin_max_w;