Staging: fbtft: Fix GPIO handling

Commit c440eee1 ("Staging: fbtft: Switch to the gpio descriptor
interface") breaks GPIO handling. In several places, checks to only set
a GPIO if it was configured ended up backwards.
I have tested this fix. The fixed driver works with a ili9486
display connected to a raspberry pi via SPI.

Fixes: c440eee1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Tested-by: Jan Sebastian Götte <linux@jaseg.net>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Jan Sebastian Götte <linux@jaseg.net>
Link: https://lore.kernel.org/r/75ada52f-afa1-08bc-d0ce-966fc1110e70@jaseg.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>