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

The pcie_bus_clk device node is already enabled in r8a7791.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>