serial: msm_serial: remove .clk_rate from debug UART
MSM serial in DEBUG UART mode is trying to set .clk_rate, but the
msm_serial_data structure does not have such property at all, so lets
remove it as otherwise it will fail compiling.
Fixes: 90023bdfe979 ("serial: msm: add debug UART") Signed-off-by: Robert Marko <robert.marko@sartura.hr> Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>