drivers: fpga: Kconfig: pedantic cleanups

Formatting of Kconfig files doesn't look so pretty, so just
take damp cloth and clean it up.

Signed-off-by: Enrico Weigelt <info@metux.net>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>