kobjects: fix up improper use of the kobject name field

A number of different drivers incorrect access the kobject name field
directly.  This is not correct as the name might not be in the array.
Use the proper accessor function instead.

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index feab124..cbfc815 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -194,7 +194,7 @@
 
 	if (!device->flags.power_manageable) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
-				device->dev.kobj.name));
+				kobject_name(&device->dev.kobj)));
 		return -ENODEV;
 	}
 	/*