iwlagn: clean up alive handling

Devices newer than 4965 don't actually send
two different versions of the ALIVE command,
so we always had a bug here since before this
patch we copy more data than we got. Remove
the iwl_init_alive_resp struct and don't use
it.

Since we also really don't need to track all
the data received in ALIVE as we only use the
error and log event tables later, we can also
save space by just keeping those and not more
data around in memory.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>