cciss: change Cmd_sg_list.sg_chain_dma type to dma_addr_t

A recent commit broke the ia64 build:

	Author: Don Brace <brace@beardog.cce.hp.com>
	Date:   Thu Nov 12 12:50:01 2009 -0600

	cciss: Add enhanced scatter-gather support.

because of this hunk:

	--- a/drivers/block/cciss.h
	+++ b/drivers/block/cciss.h
	+struct Cmd_sg_list {
	+       SGDescriptor_struct     *sgchain;
	+       dma64_addr_t            sg_chain_dma;
	+       int                     chain_block_size;
	+};

The issue is that dma64_addr_t isn't #define'd on ia64.

The way that we're using Cmd_sg_list.sg_chain_dma is to hold an
address returned from pci_map_single().

	+               temp64.val = pci_map_single(h->pdev,
	+                                 h->cmd_sg_list[c->cmdindex]->sgchain,
	+                                 len, dir);
	+
	+               h->cmd_sg_list[c->cmdindex]->sg_chain_dma = temp64.val;

pci_map_single() returns a dma_addr_t too.

This code will still work even on a 32-bit x86 build, where
dma_addr_t is defined to be a u32 because it will simply be
promoted to the __u64 that temp64.val is defined as.

Thus, declaring Cmd_sg_list.sg_chain_dma as dma_addr_t is safe.

Cc: Don Brace <brace@beardog.cce.hp.com>
Cc: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>