mwl8787: remove #if 0-ed code

I'm not sure whether we will need any of this:
 - tx buffer size is used for amsdu, but not ampdu
 - getting TX power is informational (it is used to limit config
   requests from userspace, but mac80211 doesn't do that)
 - not sure what getting the tx rate even means
 - ibss merging should be handled by the stack

Signed-off-by: Bob Copeland <me@bobcopeland.com>
mwl8787: import the multiport sdio tx aggr code

Lots of cleanup needed here, but seems to work ok (approx. same as without).

Signed-off-by: Bob Copeland <me@bobcopeland.com>