pwm: bcm-iproc: handle clk_get_rate() return
Handle clk_get_rate() returning 0 to avoid possible division by zero. Fixes: daa5abc4 ("pwm: Add support for Broadcom iProc PWM controller") Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> Signed-off-by: Scott Branden <scott.branden@broadcom.com> Reviewed-by: Ray Jui <ray.jui@broadcom.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>