mtd: rawnand: orion: Use helper function devm_clk_get_optional_enabled()

Since commit 7ef9651e ("clk: Provide new devm_clk helpers for prepared
and enabled clocks"), devm_clk_get_optional() and clk_prepare_enable() can
now be replaced by devm_clk_get_optional_enabled() when driver enables
(and possibly prepares) the clocks for the whole lifetime of the device.
Moreover, it is no longer necessary to unprepare and disable the clocks
explicitly, so drop the label "no_dev".

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230821031737.1973183-13-lizetao1@huawei.com