b43: add option to avoid duplicating device support with brcmsmac

Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/Kconfig b/drivers/net/wireless/b43/Kconfig
index b97a40e..3876c7e 100644
--- a/drivers/net/wireless/b43/Kconfig
+++ b/drivers/net/wireless/b43/Kconfig
@@ -31,6 +31,12 @@
 	depends on B43 && BCMA
 	default y
 
+config B43_BCMA_EXTRA
+	bool "Hardware support that overlaps with the brcmsmac driver"
+	depends on B43_BCMA
+	default n if BRCMSMAC || BRCMSMAC_MODULE
+	default	y
+
 config B43_SSB
 	bool
 	depends on B43 && SSB