mac80211: fix NULL ptr dereference during mesh peer connection for non HE devices

mac80211: fix NULL ptr dereference during mesh peer connection for non HE devices

"sband->iftype_data" is not assigned with any value for non HE supported
devices, which causes NULL pointer access during mesh peer connection
in those devices. Fix this by accessing the pointer after HE
capabilities condition check.

Cc: stable@vger.kernel.org
Fixes: 84f161f103be (mac80211: reduce peer HE MCS/NSS to own capabilities)
Signed-off-by: Abinaya Kalaiselvan <akalaise@codeaurora.org>
Link: https://lore.kernel.org/r/1624459244-4497-1-git-send-email-akalaise@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>