[z2270] Fix some signed/unsigned integer comparison warnings

Signed-off-by: Schmoozerd <schmoozerd@cmangos>

(based on commit [12375] - 1ba4ddb)

Signed-off-by: Xfurry <xfurry@scriptdev2.com>

(based on commit [s1909] - 3bc8931)

Signed-off-by: Xfurry <xfurry@scriptdev2.com>