[POWERPC] Check cache coherency of kernel vs firmware

check_cache_coherency() verifies that the cache coherency setting of
the kernel (CONFIG_NOT_COHERENT_CACHE) matches that left by the firmware,
as indicated by coherency-off device tree property.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ccc5410..64089b1 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -389,6 +389,9 @@
 	bool
 	depends on 4xx || 8xx || E200
 	default y
+
+config CONFIG_CHECK_CACHE_COHERENCY
+	bool
 endmenu
 
 source "init/Kconfig"