qcacmn: fix index overflow when tso seg large

In some cases, TSO segment may larger than 255.
If use uint8 as the loop index, tx logic will
overflow and sending the last segment repeatly,
then lead to buffer double free. Change index
variable to uint32

CRs-Fixed: 2722918

Change-Id: I156a5d8b8a3895e4f7bfc53cf5561f51ca8b06ca