qcacmn: Fix OOB Read in util_gen_new_ie

In util_gen_new_ie, there is a possible out-of-bound read due to a missing
length check for extended IEs in the final pass over the copied
subelements.
Fix is to check tmp_new[1] is not zero.

Change-Id: Ic393d699a208bb54ff645bd8d2424b84becf5543
CRs-Fixed: 3924648