[SG] Update drivers to use sg helpers

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 52d0b87..d1780980 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -515,8 +515,7 @@
 	if (cmd->use_sg) {
 		cmd->SCp.buffer = (struct scatterlist *)cmd->request_buffer;
 		cmd->SCp.buffers_residual = cmd->use_sg - 1;
-		cmd->SCp.ptr = (char *)page_address(cmd->SCp.buffer->page) +
-			       cmd->SCp.buffer->offset;
+		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
 		cmd->SCp.this_residual = cmd->SCp.buffer->length;
 		/* ++roman: Try to merge some scatter-buffers if they are at
 		 * contiguous physical addresses.
@@ -2054,8 +2053,7 @@
 					++cmd->SCp.buffer;
 					--cmd->SCp.buffers_residual;
 					cmd->SCp.this_residual = cmd->SCp.buffer->length;
-					cmd->SCp.ptr = page_address(cmd->SCp.buffer->page) +
-						   cmd->SCp.buffer->offset;
+					cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
 					/* ++roman: Try to merge some scatter-buffers if
 					 * they are at contiguous physical addresses.
 					 */