configs: correct memory configuration
    
    The shipped .config files all have CONFIG_FLATMEM_MANUAL and
    CONFIG_SPARSEMEM_MANUAL set.
    
    This is wrong because each .config should have just one of these two set
    set. (There's also CONFIG_DISCONTIGMEM_MANUAL but Fedora doesn't use
    that.) As a result the build generates
        [...]:warning: override: SPARSEMEM_MANUAL changes choice state
    
    24 times.
    
    If the configuration generation system drops CONFIG_FLATMEM_MANUAL the
    warnings go away. And that doesn't change the final .config files that
    the kernel's build system actually uses.
    
    (Two details that very few people will care about:
    1. x86/i686 still needs to unset CONFIG_FLATMEM_MANUAL to keep
    process_configs.sh from killing the build;
    2. the kernel build of armv7hl will silently drop
    CONFIG_SPARSEMEM_MANUAL. Because of that I didn't bother with an
    explicit override for arm/armv7.)
    
    Signed-off-by: Paul Bolle <pebolle@tiscali.nl>