src: Missing limits.h includes

Latest git doesn't compile for me on Fedora 9 due to various *MAX constants
being undefined.  Below adds the include in 3 files which need it (although
I can't see why this isn't required in 1.4.1.1).

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
3 files changed