mtd: mxc_nand: Adapt the clock name to the new clock framework

With the new i.mx clock framework the mxc_nand clock is registered as:

clk_register_clkdev(clk[nfc_gate], NULL, "mxc_nand");0")

So we do not need to pass "nfc" string and can use NULL instead.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/mxc_nand.c

@@ -1399,7 +1399,7 @@ static int __devinit mxcnd_probe(struct platform_device *pdev)
 	this->write_buf = mxc_nand_write_buf;
 	this->read_buf = mxc_nand_read_buf;
 
-	host->clk = devm_clk_get(&pdev->dev, "nfc");
+	host->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(host->clk))
 		return PTR_ERR(host->clk);