[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/sun3x_esp.c b/drivers/scsi/sun3x_esp.c
index 1f328ca..6b60536 100644
--- a/drivers/scsi/sun3x_esp.c
+++ b/drivers/scsi/sun3x_esp.c
@@ -347,7 +347,7 @@
 static void dma_mmu_release_scsi_sgl (struct NCR_ESP *esp, Scsi_Cmnd *sp)
 {
     int sz = sp->use_sg - 1;
-    struct scatterlist *sg = (struct scatterlist *)sp->buffer;
+    struct scatterlist *sg = (struct scatterlist *)sp->request_buffer;
                         
     while(sz >= 0) {
         dvma_unmap((char *)sg[sz].dma_address);