block: blk_rq_[cur_]_{sectors|bytes}() usage cleanup

With the previous changes, the followings are now guaranteed for all
requests in any valid state.

* blk_rq_sectors() == blk_rq_bytes() >> 9
* blk_rq_cur_sectors() == blk_rq_cur_bytes() >> 9

Clean up accessor usages.  Notable changes are

* nbd,i2o_block: end_all used instead of explicit byte count
* scsi_lib: unnecessary conditional on request type removed

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/mtd/mtd_blkdevs.c

@@ -48,7 +48,7 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 	char *buf;
 
 	block = blk_rq_pos(req) << 9 >> tr->blkshift;
-	nsect = blk_rq_cur_sectors(req) << 9 >> tr->blkshift;
+	nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
 
 	buf = req->buffer;