pch_dma: Fix suspend issue

Currently, executing suspend/hibernation,
memory access violation occurs.

In pch_dma_save_regs() called by suspend(),
you can see the following code.

static void pch_dma_save_regs(struct pch_dma *pd)
{
snip...
        list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
                pd_chan = to_pd_chan(chan);

                pd->ch_regs[i].dev_addr = channel_readl(pd_chan, DEV_ADDR);
                pd->ch_regs[i].mem_addr = channel_readl(pd_chan, MEM_ADDR);
                pd->ch_regs[i].size = channel_readl(pd_chan, SIZE);
                pd->ch_regs[i].next = channel_readl(pd_chan, NEXT);

                i++;
        }
}

Max loop count is 12 defined at pci_table.
So, this caused memory access violation.

This patch fixes the issue
 - Modify array size (MAX_CHAN_NR)

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.lapis-semi.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>