platform/x86: fujitsu-laptop: remove redundant forward declarations

Both acpi_fujitsu_bl_notify() and acpi_fujitsu_laptop_notify() are
defined before they are first used, so remove their forward declarations
as they are redundant.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
[kempniu: rebase patch, rewrite commit message]
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>