KCM: Do not use 2048 as fixed size for the payload
The KCM code has the limit set as 2048 only inside #ifdef __APPLE__,
while it should be normally set as 10 * 1024 * 1024, as seen in:
Last but not least, doesn't make much sense to use a fixed value as the
first 4 bytes received are the payload size ... so let's just allocate
the needed size instead of having a fixed value.
Signed-off-by: Fabiano Fidêncio <email@example.com>
Reviewed-by: Jakub Hrozek <firstname.lastname@example.org>