mt76: mt7915: add sta_rec with EXTRA_INFO_NEW for the first time only

Set EXTRA_INFO_NEW for the first time only to prevent adding the same
starec entry, otherwise the entry might be removed in fw.

Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>