brcmfmac: rename structure brcmf_cfg80211_priv

Renamed structure to brcmf_cfg80211_info as it is not really a
private structure since it is exposed in header file.

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