clk: renesas: rzv2h: remove round_rate() in favor of determine_rate()

clk: renesas: rzv2h: remove round_rate() in favor of determine_rate()

This driver implements both the determine_rate() and round_rate() clk
ops, and the round_rate() clk ops is deprecated. When both are defined,
clk_core_determine_round_nolock() from the clk core will only use the
determine_rate() clk ops, so let's remove the round_rate() clk ops since
it's unused.

Signed-off-by: Brian Masney <bmasney@redhat.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250811-clk-for-stephen-round-rate-v1-93-b3bf97b038dc@redhat.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>