mtd: rawnand: rockchip: Check before clk_disable_unprepare() not needed

All code in clk_disable_unprepare() already checks the clk ptr using
IS_ERR_OR_NULL so there is no need to check it again before calling it.
A lot of other drivers already rely on this behaviour, so it's safe
to do so here.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220512184558.45966-1-phil.edworthy@renesas.com

drivers/mtd/nand/raw/rockchip-nand-controller.c

@@ -911,7 +911,6 @@ static int rk_nfc_enable_clks(struct device *dev, struct rk_nfc *nfc)
 	ret = clk_prepare_enable(nfc->ahb_clk);
 	if (ret) {
 		dev_err(dev, "failed to enable ahb clk\n");
-		if (!IS_ERR(nfc->nfc_clk))
 		clk_disable_unprepare(nfc->nfc_clk);
 		return ret;
 	}
@@ -921,7 +920,6 @@ static int rk_nfc_enable_clks(struct device *dev, struct rk_nfc *nfc)
 
 static void rk_nfc_disable_clks(struct rk_nfc *nfc)
 {
-	if (!IS_ERR(nfc->nfc_clk))
 	clk_disable_unprepare(nfc->nfc_clk);
 	clk_disable_unprepare(nfc->ahb_clk);
 }