clk: rockchip: fix function type for CLK_OF_DECLARE

Adding function type checking to CLK_OF_DECLARE found a type mismatch with
rk2928_gate_clk_init. The function only takes a single struct device_node
parameter.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Mike Turquette <mturquette@linaro.org>