b43legacy: move under broadcom vendor directory

MAINTAINERS

drivers/net/wireless/Kconfig

drivers/net/wireless/Makefile

drivers/net/wireless/broadcom/Kconfig

drivers/net/wireless/broadcom/Makefile

drivers/net/wireless/broadcom/b43legacy/Kconfig

drivers/net/wireless/broadcom/b43legacy/Makefile

drivers/net/wireless/broadcom/b43legacy/b43legacy.h

drivers/net/wireless/broadcom/b43legacy/debugfs.c

drivers/net/wireless/broadcom/b43legacy/debugfs.h

drivers/net/wireless/broadcom/b43legacy/dma.c

drivers/net/wireless/broadcom/b43legacy/dma.h

drivers/net/wireless/broadcom/b43legacy/ilt.c

drivers/net/wireless/broadcom/b43legacy/ilt.h

drivers/net/wireless/broadcom/b43legacy/leds.c

drivers/net/wireless/broadcom/b43legacy/leds.h

drivers/net/wireless/broadcom/b43legacy/main.c

drivers/net/wireless/broadcom/b43legacy/main.h

drivers/net/wireless/broadcom/b43legacy/phy.c

drivers/net/wireless/broadcom/b43legacy/phy.h