brcmfmac: fix p2p scan abort null pointer exception

When p2p connection setup is performed without having ever done an
escan a null pointer exception can occur. This is because the ifp
to abort scanning is taken from escan struct while it was never
initialized. Fix this by using the primary ifp for scan abort. The
abort should still be performed and all scan related commands are
performed on primary ifp.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Signed-off-by: Hante Meuleman <hante.meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>