mwl8787: send hw_spec cmd synchronously

Wait for it so we know when we have the mac addr.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
mwl8787: add action flag for GET

Signed-off-by: Bob Copeland <me@bobcopeland.com>
mwl8787: move firmware loading to probe

In order to read the mac address and other settings we need to
load firmware first, so start that in probe and put off
registering the device with mac80211 until we get the hardware
info.

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