[WATCHDOG] fix clk_get() error check

The return value of clk_get() should be checked by IS_ERR().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/char/watchdog/pnx4008_wdt.c b/drivers/char/watchdog/pnx4008_wdt.c
index 3a55fc6..0e3d589 100644
--- a/drivers/char/watchdog/pnx4008_wdt.c
+++ b/drivers/char/watchdog/pnx4008_wdt.c
@@ -283,7 +283,8 @@
 	wdt_base = (void __iomem *)IO_ADDRESS(res->start);
 
 	wdt_clk = clk_get(&pdev->dev, "wdt_ck");
-	if (!wdt_clk) {
+	if (IS_ERR(wdt_clk)) {
+		ret = PTR_ERR(wdt_clk);
 		release_resource(wdt_mem);
 		kfree(wdt_mem);
 		goto out;