[ARM] pxa/pcm990: use negative number for an invalid GPIO in camera data

0 is a valid GPIO number, use a negative number to specify, that this camera
doesn't have a GPIO for bus-width switching.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/arch/arm/mach-pxa/pcm990-baseboard.c b/arch/arm/mach-pxa/pcm990-baseboard.c
index f601425..b36cec5c 100644
--- a/arch/arm/mach-pxa/pcm990-baseboard.c
+++ b/arch/arm/mach-pxa/pcm990-baseboard.c
@@ -385,6 +385,7 @@
 		.gpio	= NR_BUILTIN_GPIO + 1,
 	}, {
 		.bus_id	= 0, /* Must match with the camera ID above */
+		.gpio	= -ENXIO,
 	}
 };