rpi: copy over uart clock-frequency in DT

rpi5 firmware sets uart_clk clock-frequency in
the firmware and patches it to the DT, copy it
over when loading a new DT.

Signed-off-by: Bruno Leite <brule@prevas.dk>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
1 file changed