cachefiles: Remove the now superfluous sentinel element from ctl_table array

This commit comes at the tail end of a greater effort to remove the empty
elements at the end of the ctl_table arrays (sentinels) which will reduce the
overall build time size of the kernel and run time memory bloat by ~64 bytes
per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/

)

Remove sentinel from cachefiles_sysctls

Signed-off-by: Joel Granados <j.granados@samsung.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>