mtd: spi-nor: constify fsl_qspi_devtype_data

All fsl_qspi_devtype_data structures are never modified.
This patch constify them.

Signed-off-by: LABBE Corentin <[e-mail]>
Acked-by: Han Xu <[e-mail]>
Signed-off-by: Cyrille Pitchen <[e-mail]>

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

···
 	int driver_data;
 };
 
-static struct fsl_qspi_devtype_data vybrid_data = {
+static const struct fsl_qspi_devtype_data vybrid_data = {
 	.devtype = FSL_QUADSPI_VYBRID,
 	.rxfifo = 128,
 	.txfifo = 64,
···
 	.driver_data = QUADSPI_QUIRK_SWAP_ENDIAN,
 };
 
-static struct fsl_qspi_devtype_data imx6sx_data = {
+static const struct fsl_qspi_devtype_data imx6sx_data = {
 	.devtype = FSL_QUADSPI_IMX6SX,
 	.rxfifo = 128,
 	.txfifo = 512,
···
 		       | QUADSPI_QUIRK_TKT245618,
 };
 
-static struct fsl_qspi_devtype_data imx7d_data = {
+static const struct fsl_qspi_devtype_data imx7d_data = {
 	.devtype = FSL_QUADSPI_IMX7D,
 	.rxfifo = 512,
 	.txfifo = 512,
···
 		       | QUADSPI_QUIRK_4X_INT_CLK,
 };
 
-static struct fsl_qspi_devtype_data imx6ul_data = {
+static const struct fsl_qspi_devtype_data imx6ul_data = {
 	.devtype = FSL_QUADSPI_IMX6UL,
 	.rxfifo = 128,
 	.txfifo = 512,