pico-imx7d: Correct uart clock root

Correct uart clock root ID. Incorrect ID may result the
clock is gated because rate value 0 is returned in
imx_get_uartclk()

The ID can be ignored if CONFIG_SKIP_LOWLEVEL_INIT is not enabled
because init_clk_uart() will enable all uart clocks in that case.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
2 files changed