mtd: spi-nor: cqspi: make of_device_ids const

of_device_ids are not supposed to change at runtime. All functions
working with of_device_ids provided by <linux/of.h> work with const
of_device_ids. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>

drivers/mtd/spi-nor/cadence-quadspi.c

@@ -1283,7 +1283,7 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
 #define CQSPI_DEV_PM_OPS	NULL
 #endif
 
-static struct of_device_id const cqspi_dt_ids[] = {
+static const struct of_device_id const cqspi_dt_ids[] = {
 	{.compatible = "cdns,qspi-nor",},
 	{ /* end of table */ }
 };