ide: constify struct ide_dma_ops

* Export ide_dma_exec_cmd() and __ide_dma_test_irq().

* Constify struct ide_dma_ops.

* Always set hwif->dma_ops to &sff_dma_ops in ide_setup_dma()
  (it is later overriden by ide_init_port() if needed) and drop
  'const struct ide_port_info *d' argument.

While at it:

* Rename __ide_dma_test_irq() to ide_dma_test_irq().

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/mips/au1xxx-ide.c b/drivers/ide/mips/au1xxx-ide.c
index 579caa3..3485a31 100644
--- a/drivers/ide/mips/au1xxx-ide.c
+++ b/drivers/ide/mips/au1xxx-ide.c
@@ -380,7 +380,7 @@
 	auide_dma_end(drive);
 }
 
-static struct ide_dma_ops au1xxx_dma_ops = {
+static const struct ide_dma_ops au1xxx_dma_ops = {
 	.dma_host_set		= auide_dma_host_set,
 	.dma_setup		= auide_dma_setup,
 	.dma_exec_cmd		= auide_dma_exec_cmd,