gpu: ipu-v3: do not divide by zero if the pixel clock is too large

Even if an unsupported mode with a pixel clock larger than two times the
264 MHz IPU HSP clock is set, don't divide by zero.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/ipu-v3/ipu-di.c

@@ -459,6 +459,8 @@ static void ipu_di_config_clock(struct ipu_di *di,
 
 		clkrate = clk_get_rate(di->clk_ipu);
 		div = DIV_ROUND_CLOSEST(clkrate, sig->mode.pixelclock);
+		if (div == 0)
+			div = 1;
 		rate = clkrate / div;
 
 		error = rate / (sig->mode.pixelclock / 1000);