brcm80211: fmac: move driver up status to struct brcmf_bus

brcm80211: fmac: move driver up status to struct brcmf_bus

Driver up/down status to network interface need to be shared by
common layer and bus layer. Move it to bus interface structure
brcmf_bus as part of the fullmac bus interface refactoring.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>