misc/pvpanic-mmio: Fix error handling in 'pvpanic_mmio_probe()'

There is no error handling path in the probe function.
Switch to managed resource so that errors in the probe are handled easily
and simplify the remove function accordingly.

Fixes: b3c0f87 ("misc/pvpanic: probe multiple instances")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/2a5dab18f10db783b27e0579ba66cc38d610734a.1621665058.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/pvpanic/pvpanic-mmio.c

@@ -93,7 +93,7 @@ static int pvpanic_mmio_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
+	pi = devm_kmalloc(dev, sizeof(*pi), GFP_ATOMIC);
 	if (!pi)
 		return -ENOMEM;
 
@@ -114,7 +114,6 @@ static int pvpanic_mmio_remove(struct platform_device *pdev)
 	struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
 
 	pvpanic_remove(pi);
-	kfree(pi);
 
 	return 0;
 }