NetworkPkg: better sanity check on Ipv6 prefix length

Fix a possible buffer overrun issue that could occur if PrefixLength >
128 . Changed == 128 to >= 128. Also remove check for Byte < 16, which
is no longer possible because of the first change.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Samer El-Haj-Mahmoud <elhaj@hpe.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
1 file changed