avr32: boards: setup: use IS_ERR() instead of NULL check

clk_get() returns ERR_PTR() on error, not NULL.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>

arch/avr32/boards/atstk1000/atstk1002.c

@@ -203,7 +203,7 @@ static void __init set_hw_addr(struct platform_device *pdev)
 	 */
 	regs = (void __iomem __force *)res->start;
 	pclk = clk_get(&pdev->dev, "pclk");
-	if (!pclk)
+	if (IS_ERR(pclk))
 		return;
 
 	clk_enable(pclk);