brcm80211: smac: some local function made static in main.c

In main.c a couple of functions were not static although they
were only locally used. Sparse gave warnings on them and these
functions have been made static.

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