clk: imx: imx93: invoke imx_register_uart_clocks

Invoke imx_register_uart_clocks to keep uart clk on when earlycon
specified.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20230104110032.1220721-5-peng.fan@oss.nxp.com