linux-imx

clk: imx7ulp: call imx_register_uart_clocks once during clocks reigster

imx_register_uart_clocks() only support once call during platform
clocks register. So use one gobal pcc_uart_clks[] array instead of
two array.

Fixes: 041652514d8b(clk: imx7ulp: Make sure earlycon's clock is enabled)
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>