sh: remove sh5 support

sh5 never became a product and has probably never really worked.

Remove it by recursively deleting all associated Kconfig options
and all corresponding files.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rich Felker <dalias@libc.org>

arch/sh/mm/cache.c

@@ -355,12 +355,6 @@ void __init cpu_cache_init(void)
 		}
 	}
 
-	if (boot_cpu_data.family == CPU_FAMILY_SH5) {
-		extern void __weak sh5_cache_init(void);
-
-		sh5_cache_init();
-	}
-
 skip:
 	emit_cache_params();
 }