fm4: Add support for MB9BFx64/x65

These appear to be just additional flash size configurations.
Entirely based on manual, untested.

Change-Id: I4460dc1a588335df8fc0a385d24513a4e35b6951
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-on: http://openocd.zylin.com/3157


Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>