mtd: rawnand: meson: Fix a resource leak in init

Call clk_disable_unprepare(nfc->phase_rx) if the clk_set_rate() function
fails to avoid a resource leak.

Fixes: 8fae856c ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/X8ikVCnUsfTpffFB@mwanda