gpio: of: fix Freescale SPI CS quirk handling

On the gta04 we see:
spi_gpio: probe of spi_lcd failed with error -2

The quirk introduced in
commit e3023bf8 ("gpio: of: Handle the Freescale SPI CS")
can also be triggered by a temporary -EPROBE_DEFER and
so "convert" it to a hard -ENOENT.

Disable that conversion by checking for -EPROBE_DEFER.

Fixes: e3023bf8 ("gpio: of: Handle the Freescale SPI CS")
Suggested-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Link: https://lore.kernel.org/r/20190816165000.32334-1-andreas@kemnade.infoSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-of.c

@@ -363,7 +363,7 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
 	/* Special handling for SPI GPIOs if used */
 	if (IS_ERR(desc))
 		desc = of_find_spi_gpio(dev, con_id, &of_flags);
-	if (IS_ERR(desc)) {
+	if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER) {
 		/* This quirk looks up flags and all */
 		desc = of_find_spi_cs_gpio(dev, con_id, idx, flags);
 		if (!IS_ERR(desc))