target: Minimize SCSI header #include directives

Only include SCSI initiator header files in target code that needs
these header files, namely the SCSI pass-through code and the tcm_loop
driver. Change SCSI_SENSE_BUFFERSIZE into TRANSPORT_SENSE_BUFFER in
target code because the former is intended for initiator code and the
latter for target code. With this patch the only initiator include
directives in target code that remain are as follows:

$ git grep -nHE 'include .scsi/(scsi.h|scsi_host.h|scsi_device.h|scsi_cmnd.h)' drivers/target drivers/infiniband/ulp/{isert,srpt} drivers/usb/gadget/legacy/tcm_*.[ch] drivers/{vhost,xen} include/{target,trace/events/target.h}
drivers/target/loopback/tcm_loop.c:29:#include <scsi/scsi.h>
drivers/target/loopback/tcm_loop.c:31:#include <scsi/scsi_host.h>
drivers/target/loopback/tcm_loop.c:32:#include <scsi/scsi_device.h>
drivers/target/loopback/tcm_loop.c:33:#include <scsi/scsi_cmnd.h>
drivers/target/target_core_pscsi.c:39:#include <scsi/scsi_device.h>
drivers/target/target_core_pscsi.c:40:#include <scsi/scsi_host.h>
drivers/xen/xen-scsiback.c:52:#include <scsi/scsi_host.h> /* SG_ALL */

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 0203774..aec6f6a 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -6,7 +6,6 @@
 #include <linux/dma-mapping.h>
 #include <linux/blkdev.h>
 #include <linux/percpu_ida.h>
-#include <scsi/scsi_cmnd.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 
@@ -25,7 +24,7 @@
  * From include/scsi/scsi_cmnd.h:SCSI_SENSE_BUFFERSIZE, currently
  * defined 96, but the real limit is 252 (or 260 including the header)
  */
-#define TRANSPORT_SENSE_BUFFER			SCSI_SENSE_BUFFERSIZE
+#define TRANSPORT_SENSE_BUFFER			96
 /* Used by transport_send_check_condition_and_sense() */
 #define SPC_SENSE_KEY_OFFSET			2
 #define SPC_ADD_SENSE_LEN_OFFSET		7