can: phytium: Convert to platform remove callback returning void

0edb555: platform: Make platform_driver::remove() return void
cause build error, so convert .remove from int to void

Log:
drivers/net/can/phytium/phytium_can_platform.c:220:19: error: initialization of ‘void (*)(struct platform_device *)’ from incompatible pointer type ‘int (*)(struct platform_device *)’ [-Werror=incompatible-pointer-types]
  220 |         .remove = phytium_can_plat_remove,
      |                   ^~~~~~~~~~~~~~~~~~~~~~~
drivers/net/can/phytium/phytium_can_platform.c:220:19: note: (near initialization for ‘phytium_can_plat_driver.<anonymous>.remove’)

drivers/net/can/phytium/phytium_can_platform.c

@@ -173,16 +173,14 @@ static __maybe_unused int phytium_can_plat_resume(struct device *dev)
 	return phytium_can_resume(dev);
 }
 
-static int phytium_can_plat_remove(struct platform_device *pdev)
+static void phytium_can_plat_remove(struct platform_device *pdev)
 {
 	struct net_device *dev = platform_get_drvdata(pdev);
 	struct phytium_can_dev *cdev = netdev_priv(dev);
 
 	phytium_can_unregister(cdev);
 
 	phytium_can_free_dev(cdev->net);
-
-	return 0;
 }
 
 static int __maybe_unused phytium_can_runtime_suspend(struct device *dev)