drm/xe: Fix a NULL vs IS_ERR() bug in xe_i2c_register_adapter()

The fwnode_create_software_node() function returns error pointers.  It
never returns NULL.  Update the checks to match.

Fixes: f0e53aa ("drm/xe: Support for I2C attached MCUs")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/65825d00-81ab-4665-af51-4fff6786a250@sabinyo.mountain
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: Dan Carpenter

drivers/gpu/drm/xe/xe_i2c.c

@@ -96,8 +96,8 @@ static int xe_i2c_register_adapter(struct xe_i2c *i2c)
 	int ret;
 
 	fwnode = fwnode_create_software_node(xe_i2c_adapter_properties, NULL);
-	if (!fwnode)
-		return -ENOMEM;
+	if (IS_ERR(fwnode))
+		return PTR_ERR(fwnode);
 
 	/*
 	 * Not using platform_device_register_full() here because we don't have