nl80211: use NLA_POLICY_RANGE(NLA_BINARY, ...) for a few attributes

We have a few attributes with minimum and maximum lengths that are
not the same, use the new feature of being able to specify both in
the policy to validate them, removing code and allowing this to be
advertised to userspace in the policy export.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200819085642.8f12ffa14f33.I9d948d59870e521febcd79bb4a986b1de1dca47b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>