firmware_loader: remove unused exports

Neither fw_fallback_config nor firmware_config_table are used by modules.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200417064146.1086644-3-hch@lst.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>