cfg80211: pass struct to interface combination check/iter

Move the growing parameter list to a structure for the interface
combination check and iteration functions in cfg80211 and mac80211
to make the code easier to understand.

Signed-off-by: Purushottam Kushwaha <pkushwah@qti.qualcomm.com>
[edit commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>