mac80211: remove unnecessary NULL check in ieee80211_register_hw()

The address "&sband->iftype_data[i]" points to an array at the end of
struct.  It can't be NULL and so the check can be removed.

Fixes: bac2fd3d ("mac80211: remove use of ieee80211_get_he_sta_cap()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YNmgHi7Rh3SISdog@mwanda


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