staging: fbtft: Don't spam logs when probe is deferred

When requesting GPIO line the probe can be deferred.
In such case don't spam logs with an error message.
This can be achieved by switching to dev_err_probe().

Fixes: c440eee1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-3-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fbtft-core.c

@@ -75,20 +75,16 @@ static int fbtft_request_one_gpio(struct fbtft_par *par,
 				  struct gpio_desc **gpiop)
 {
 	struct device *dev = par->info->device;
-	int ret = 0;
 
 	*gpiop = devm_gpiod_get_index_optional(dev, name, index,
 					       GPIOD_OUT_LOW);
-	if (IS_ERR(*gpiop)) {
-		ret = PTR_ERR(*gpiop);
-		dev_err(dev,
-			"Failed to request %s GPIO: %d\n", name, ret);
-		return ret;
-	}
+	if (IS_ERR(*gpiop))
+		return dev_err_probe(dev, PTR_ERR(*gpiop), "Failed to request %s GPIO\n", name);
+
 	fbtft_par_dbg(DEBUG_REQUEST_GPIOS, par, "%s: '%s' GPIO\n",
 		      __func__, name);
 
-	return ret;
+	return 0;
 }
 
 static int fbtft_request_gpios(struct fbtft_par *par)