ARM: ux500: U8500 depends on MMU

There is no way to build  U8500 kernels without an MMU
at this point because of dependencies on MMU-only functions.

As long as nobody is interested in fixing this, let's just disable
the platforms for nommu kernels.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

arch/arm/Kconfig

@@ -901,6 +901,7 @@ config ARCH_U300
 
 config ARCH_U8500
 	bool "ST-Ericsson U8500 Series"
+	depends on MMU
 	select CPU_V7
 	select ARM_AMBA
 	select GENERIC_CLOCKEVENTS