dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

During system reboot, the sh-dma-engine device may be runtime-suspended,
causing a crash:

    Unhandled fault: imprecise external abort (0x1406) at 0x0002c02c
    Internal error: : 1406 [#1] SMP ARM
    ...
    PC is at sh_dmae_ctl_stop+0x28/0x64
    LR is at sh_dmae_ctl_stop+0x24/0x64

If the sh-dma-engine is runtime-suspended, its module clock is turned
off, and its registers cannot be accessed.

To fix this, move the call to sh_dmae_ctl_stop(), which touches the
DMAOR register, to the sh_dmae_suspend() and sh_dmae_runtime_suspend()
callbacks.  This makes PM operations more symmetric, as both
sh_dmae_resume() and sh_dmae_runtime_resume() already call sh_dmae_rst()
to re-initialize the DMAOR register.

Remove sh_dmae_shutdown(), as it became empty.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/sh/shdmac.c

@@ -582,15 +582,12 @@ static void sh_dmae_chan_remove(struct sh_dmae_device *shdev)
 	}
 }
 
-static void sh_dmae_shutdown(struct platform_device *pdev)
-{
-	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
-	sh_dmae_ctl_stop(shdev);
-}
-
 #ifdef CONFIG_PM
 static int sh_dmae_runtime_suspend(struct device *dev)
 {
+	struct sh_dmae_device *shdev = dev_get_drvdata(dev);
+
+	sh_dmae_ctl_stop(shdev);
 	return 0;
 }
 
@@ -605,6 +602,9 @@ static int sh_dmae_runtime_resume(struct device *dev)
 #ifdef CONFIG_PM_SLEEP
 static int sh_dmae_suspend(struct device *dev)
 {
+	struct sh_dmae_device *shdev = dev_get_drvdata(dev);
+
+	sh_dmae_ctl_stop(shdev);
 	return 0;
 }
 
@@ -935,7 +935,6 @@ static struct platform_driver sh_dmae_driver = {
 		.of_match_table = sh_dmae_of_match,
 	},
 	.remove		= sh_dmae_remove,
-	.shutdown	= sh_dmae_shutdown,
 };
 
 static int __init sh_dmae_init(void)