mtd: m25p80: don't probe device which has status of 'disabled'

On some platforms such as P3060QDS, has multiple spi flashes, but they are
not available at same time, so if their status is 'disabled', which is set
by u-boot, will not be probed.
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/devices/m25p80.c

@@ -30,6 +30,7 @@
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/of_platform.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/flash.h>
@@ -823,6 +824,11 @@ static int __devinit m25p_probe(struct spi_device *spi)
 	unsigned			i;
 	struct mtd_part_parser_data	ppdata;
 
+#ifdef CONFIG_MTD_OF_PARTS
+	if (!of_device_is_available(spi->dev.of_node))
+		return -ENODEV;
+#endif
+
 	/* Platform data helps sort out which chip type we have, as
 	 * well as how this board partitions it.  If we don't have
 	 * a chip ID, try the JEDEC id commands; they'll work for most