First, we remove acpi_system_driver, since it's not really a driver, and making it its own 
object is just silly. This allows us to not have to register it, and we can hence remove
the add and remove callbacks. 

For initialization, acpi_system_add_fs() has been inlined in acpi_system_init(). The proc file
creation was cleaned up to use create_proc_read_entry() where possible. Any failures now
result in a goto Error, which prints the error message previously replicated after each
failure. We also remove all the files that were created if that happens. acpi_system_init()
was made a subsys_initcall and declared static. 

The acpi_system_exit() code and friends was removed, since it's never, ever called.