b43: adjust code to compile without SSB

Users of new (BCMA based) wireless chipsets may not want to enable SSB.
This is hopefully the last code patch for dropping SSB dependency.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/b43/Kconfig
Simple merge

diff --cc drivers/net/wireless/b43/bus.h
Simple merge

diff --cc drivers/net/wireless/b43/main.c
Simple merge