cache-utils: Change data type of parameters for flush_icache_range

The TCG targets i386 and tci needed a change of the function
prototype for w64.

This change is currently not needed here, but it can be applied
to avoid code differences.

Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>