clk: Change clk_core_init_rate_req prototype

The expectation is that a clk_rate_request structure is supposed to be
initialized using clk_core_init_rate_req(), yet the rate we want to
request still needs to be set by hand.

Let's just pass the rate as a function argument so that callers don't
have any extra work to do.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-15-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>