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.info
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>