clk: renesas: emev2: Remove obsolete clkdev registration

EMMA Mobile EV2 is a multi-platform/CCF-only platform, registering all
devices from DT, so we can remove the registration of clkdevs.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Link: https://lore.kernel.org/r/f54a30d7a9e2aa075d462db701a60b0b59c6ad0b.1686325857.git.geert+renesas@glider.be