drivers: memc: stm32_xspi_psram: fix command size in x8 mode

This patch fixes PSRAM initialization logic in x8 mode by ensuring that
the data line mode configuration accurately reflects the io-x16-mode
property specified in the device tree.

Signed-off-by: Arthur Gay <arthur.gay@marshmallow.kids>
diff --git a/drivers/memc/memc_stm32_xspi_psram.c b/drivers/memc/memc_stm32_xspi_psram.c
index 24b3285..e7c62e9 100644
--- a/drivers/memc/memc_stm32_xspi_psram.c
+++ b/drivers/memc/memc_stm32_xspi_psram.c
@@ -322,7 +322,8 @@
 	cmd.AddressMode = HAL_XSPI_ADDRESS_8_LINES;
 	cmd.AddressWidth = HAL_XSPI_ADDRESS_32_BITS;
 	cmd.AddressDTRMode = HAL_XSPI_ADDRESS_DTR_ENABLE;
-	cmd.DataMode = HAL_XSPI_DATA_16_LINES;
+	cmd.DataMode = DT_INST_PROP(0, io_x16_mode) ? HAL_XSPI_DATA_16_LINES
+						    : HAL_XSPI_DATA_8_LINES;
 	cmd.DataDTRMode = HAL_XSPI_DATA_DTR_ENABLE;
 	cmd.DummyCycles = DUMMY_CLK_CYCLES_WRITE;
 	cmd.DQSMode = HAL_XSPI_DQS_ENABLE;