[SCSI] More buffer->request_buffer changes

Seem like quite a few splipped through the cracks.  Here's a patch to
update all references I could find:

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/NCR53C9x.c b/drivers/scsi/NCR53C9x.c
index 8a4659e..085db48 100644
--- a/drivers/scsi/NCR53C9x.c
+++ b/drivers/scsi/NCR53C9x.c
@@ -911,7 +911,7 @@
 			sp->SCp.ptr =
 				(char *) virt_to_phys(sp->request_buffer);
 	} else {
-		sp->SCp.buffer = (struct scatterlist *) sp->buffer;
+		sp->SCp.buffer = (struct scatterlist *) sp->request_buffer;
 		sp->SCp.buffers_residual = sp->use_sg - 1;
 		sp->SCp.this_residual = sp->SCp.buffer->length;
 		if (esp->dma_mmu_get_scsi_sgl)