ARM: dts: silk: Drop superfluous status update for frequency override

The scif_clk device node is already enabled in r8a7794.dtsi, so there is
no need to update its status again.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>