gpio: use (!foo) instead of (foo == NULL)

Signed-off-by: Varka Bhadram <varkab@cdac.in>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-kempld.c b/drivers/gpio/gpio-kempld.c
index 443518f..6b8115f 100644
--- a/drivers/gpio/gpio-kempld.c
+++ b/drivers/gpio/gpio-kempld.c
@@ -156,7 +156,7 @@
 	}
 
 	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
-	if (gpio == NULL)
+	if (!gpio)
 		return -ENOMEM;
 
 	gpio->pld = pld;