Input: ads7846 - ratelimit the spi_sync error message

In case the touch controller is not connected, this message keeps scrolling
on the console indefinitelly. Ratelimit it to avoid filling kernel logs.

"
ads7846 spi2.1: spi_sync --> -22
"

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20240708211913.171243-1-marex@denx.de
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/ads7846.c

@@ -824,7 +824,7 @@ static void ads7846_read_state(struct ads7846 *ts)
 		m = &ts->msg[msg_idx];
 		error = spi_sync(ts->spi, m);
 		if (error) {
-			dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
+			dev_err_ratelimited(&ts->spi->dev, "spi_sync --> %d\n", error);
 			packet->ignore = true;
 			return;
 		}