driver core: auxiliary bus: Remove unneeded module bits

driver core: auxiliary bus: Remove unneeded module bits

Remove module bits in the auxiliary bus code since the auxiliary bus
cannot be built as a module and the relevant code is not needed.

Cc: Dave Ertman <david.m.ertman@intel.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161307488980.1896017.15627190714413338196.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>