rt2x00: error in configurations with mesh support disabled

commit 6ef9e2f6d12ce9e2120916804d2ddd46b954a70b upstream.

If CONFIG_MAC80211_MESH is not set, cfg80211 will now allow advertising
interface combinations with NL80211_IFTYPE_MESH_POINT present.
Add appropriate ifdefs to avoid running into errors.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
[lxiang: Backported for 3.4-stable. Removed code of simultaneous AP and mesh
 mode added in 4a5fc6d 3.9-rc1.]
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Reviewed-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>