platform/x86: fujitsu-laptop: break up complex loop condition

The loop condition in acpi_fujitsu_hotkey_release() includes an
assignment, a four-argument function call and a comparison, making it
hard to read.  Separate the assignment from the comparison to improve
readability.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Acked-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>