mtd: nand: omap2: remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/omap2.c

@@ -2087,7 +2087,6 @@ static int omap_nand_remove(struct platform_device *pdev)
 							mtd);
 	omap3_free_bch(&info->mtd);
 
-	platform_set_drvdata(pdev, NULL);
 	if (info->dma)
 		dma_release_channel(info->dma);