b43: add Kconfig option for compiling SSB driver

It is always "y" for now, b43 will not compile without CONFIG_SSB yet.
This is just a first step of dropping SSB dependency.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/Kconfig b/drivers/net/wireless/b43/Kconfig
index e02db1b..d5add69 100644
--- a/drivers/net/wireless/b43/Kconfig
+++ b/drivers/net/wireless/b43/Kconfig
@@ -31,6 +31,11 @@
 	depends on B43 && BCMA && BROKEN
 	default y
 
+config B43_SSB
+	bool
+	depends on B43 && SSB
+	default y
+
 # Auto-select SSB PCI-HOST support, if possible
 config B43_PCI_AUTOSELECT
 	bool