crypto: omap-sham - Only release DMA channel if successfully requested

In omap_sham_probe() and omap_sham_remove(), 'dd->dma_lch'
is released without checking to see if it was successfully
requested or not.  This is a bug and was identified and
reported by Dan Carpenter here:

	http://www.spinics.net/lists/devicetree/msg11023.html

Add code to only release 'dd->dma_lch' when its not NULL
(that is, when it was successfully requested).
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
CC: Joel Fernandes <joelf@ti.com>
Signed-off-by: NMark A. Greer <mgreer@animalcreek.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-sham.c

@@ -1970,7 +1970,8 @@ static int omap_sham_probe(struct platform_device *pdev)
 			crypto_unregister_ahash(
 					&dd->pdata->algs_info[i].algs_list[j]);
 	pm_runtime_disable(dev);
-	dma_release_channel(dd->dma_lch);
+	if (dd->dma_lch)
+		dma_release_channel(dd->dma_lch);
 data_err:
 	dev_err(dev, "initialization failed.\n");
 
@@ -1994,7 +1995,9 @@ static int omap_sham_remove(struct platform_device *pdev)
 					&dd->pdata->algs_info[i].algs_list[j]);
 	tasklet_kill(&dd->done_task);
 	pm_runtime_disable(&pdev->dev);
-	dma_release_channel(dd->dma_lch);
+
+	if (dd->dma_lch)
+		dma_release_channel(dd->dma_lch);
 
 	return 0;
 }