can: mcp251x: Fix regulators operation without CONFIG_REGULATOR

If CONFIG_REGULATOR is not set, devm_regulator_get() returns NULL,
so use IS_ERR_OR_NULL() macro for checks.

Signed-off-by: Alexander Shiyan <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index a8b74f8..28c11f8 100644
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -672,7 +672,7 @@
 
 static int mcp251x_power_enable(struct regulator *reg, int enable)
 {
-	if (IS_ERR(reg))
+	if (IS_ERR_OR_NULL(reg))
 		return 0;
 
 	if (enable)
@@ -1218,7 +1218,7 @@
 		priv->after_suspend = AFTER_SUSPEND_DOWN;
 	}
 
-	if (!IS_ERR(priv->power)) {
+	if (!IS_ERR_OR_NULL(priv->power)) {
 		regulator_disable(priv->power);
 		priv->after_suspend |= AFTER_SUSPEND_POWER;
 	}