ACPI: Remove unnecessary from/to-void* and to-void casts in drivers/acpi

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 98099de..1368783 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -427,7 +427,7 @@
 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;
 
-	mem_device = (struct acpi_memory_device *)acpi_driver_data(device);
+	mem_device = acpi_driver_data(device);
 	kfree(mem_device);
 
 	return 0;