powerpc: Make STRICT_MM_TYPECHECKS a config option

The STRICT_MM_TYPECHECKS code has bit-rotted over the years. To make it
possible to easily build test it, make it a CONFIG option.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig.debug

@@ -19,6 +19,14 @@ config PPC_WERROR
 	depends on !PPC_DISABLE_WERROR
 	default y
 
+config STRICT_MM_TYPECHECKS
+	bool "Do extra type checking on mm types"
+	default n
+	help
+	  This option turns on extra type checking for some mm related types.
+
+	  If you don't know what this means, say N.
+
 config PRINT_STACK_DEPTH
 	int "Stack depth to print" if DEBUG_KERNEL
 	default 64