[PATCH] samples: build configfs sample on when enabled

[Christoph Hellwig]

On Mon, Oct 12, 2015 at 04:14:16PM +0200, Arnd Bergmann wrote:
> Most samples have their own Kconfig option, but for some reason
> the configfs sample does not have one and gets built unconditionally
> when CONFIG_SAMPLES is enabled, which fails if CONFIG_CONFIGFS_FS
> is not:
> 
> ERROR: "configfs_unregister_subsystem" [samples/configfs/configfs_sample.ko] undefined!
> ERROR: "configfs_register_subsystem" [samples/configfs/configfs_sample.ko] undefined!
> 
> This adds a new Kconfig symbol to mirror the existing method and
> only let the user enable this sample if configfs is present.
> 
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>

This should already be in version two of the series I sent last week.