wifi: mac80211: sta_info: fix a missing kernel-doc struct element

struct link_sta_info has now a cur_max_bandwidth data:

	net/mac80211/sta_info.h:569: warning: Function parameter or member 'cur_max_bandwidth' not described in 'link_sta_info'

Copy the meaning from struct sta_info, documenting it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: https://lore.kernel.org/r/37d898634bb30776442a33833c48cbb21c90ecc6.1656409369.git.mchehab@kernel.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>