ext_capab/ext_capab_len do not include ID and Length so no extra +2
offset should be used. This fixes a regression from commit
faf427645a ('TDLS: Use proper IE parsing
routine for non-EAPOL-Key cases') that replaced the IE parser without
noticing the difference in the pointer offset.
Signed-off-by: Flavia Vanetti <flavia.vanetti@ceva-dsp.com>