m68k: add OF control support to m68k

Add SUPPORT_OF_CONTROL at this stage, to avoid to break build
bisectability.

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
diff --git a/arch/Kconfig b/arch/Kconfig
index 239289b..e574b0d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -28,6 +28,7 @@
 	select HAVE_PRIVATE_LIBGCC
 	select SYS_BOOT_GET_CMDLINE
 	select SYS_BOOT_GET_KBD
+	select SUPPORT_OF_CONTROL
 
 config MICROBLAZE
 	bool "MicroBlaze architecture"