ste_dma40: Delete an unnecessary check before the function call "kmem_cache_destroy"

The kmem_cache_destroy() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/ste_dma40.c

@@ -3694,8 +3694,7 @@ static int __init d40_probe(struct platform_device *pdev)
 
 failure:
 	if (base) {
-		if (base->desc_slab)
-			kmem_cache_destroy(base->desc_slab);
+		kmem_cache_destroy(base->desc_slab);
 		if (base->virtbase)
 			iounmap(base->virtbase);