platform/x86: fujitsu-laptop: remove redundant fields from struct fujitsu_bl

The dev field of struct fujitsu_bl is assigned in acpi_fujitsu_bl_add(),
but never used afterwards.  brightness_changed is set in get_lcd_level()
and then its value is only printed in a debug message, so it does not
influence execution flow.  Remove both fields as they are redundant.
Update the aforementioned debug message.  Adjust whitespace to make
checkpatch happy.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>