clk: Remove redundant clk_core_init_rate_req() call

Since all the users of clk_core_round_rate_nolock() will now properly
initialize, there's no need for it to initialize the request itself.

This is even dangerous, as if the clock cannot change its rate by itself
and has CLK_SET_RATE_PARENT, clk_core_round_rate_nolock() will call
itself with the parent clock but the client clk_rate_request structure.

We will then reinitialize the child request with the parent context
(parent, boundaries, etc.), which is an issue if the parent ever changes
its own parent or parent rate.

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>