rockchip: clk: rk3399: allow requests for all UART clocks

rockchip: clk: rk3399: allow requests for all UART clocks

This patch adds the rate for UART1 and UART3 the same way
as already implemented for UART0 and UART2.

This is required for boards, which have their console output
on these UARTs.

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>