Although commit 882164a4a928 ("ssb: Prevent build of PCI host features in module") appeared to be harmless, it leads to complete failure of drivers b43. and b43legacy, and likely affects b44 as well. The problem is that CONFIG_SSB_PCIHOST is undefined, which prevents the compilation of the code that controls the PCI cores of the device. See https://bugzilla.redhat.com/show_bug.cgi?id=1572349 for details.
As the underlying errors ("pcibios_enable_device" undefined, and "register_pci_controller" undefined) do not appear on the architectures that I have tested (x86_64, x86, and ppc), I suspect something in the arch-specific code for your setup (MIPS?). As I have no idea on how to fix that problem, would the following patch work for you?
diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
index 9371651d8017..3743533c8057 100644
@@ -117,7 +117,7 @@ config SSB_SERIAL
-ÂÂÂÂÂÂ depends on SSB_PCIHOST && SSB = y
+ÂÂÂÂÂÂ depends on SSB_PCIHOST && (SSB = y || !MIPS)
ÂÂÂÂÂÂÂ default y