SH-4 has nommu variants, whereas SH-3 does not.

extra/Configs/Config.sh

@@ -62,7 +62,6 @@ config CONFIG_SH3
 	bool "SH3"
 
 config CONFIG_SH4
-	select ARCH_HAS_MMU
 	select FORCE_SHAREABLE_TEXT_SEGMENTS
 	bool "SH4"