brcmfmac: Fix p2p setup when connected to ap on 5G.

The firmware requires that on p2p setup when net interfaces
are created or updated that they start initially with the same
channel as the channel in use for the current connection
(if any). If none exists take default channel 11.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>