drivers: flash: restore stm32 xspi mutex on memory mapping

Fix stm32 XSPI driver to restore the bus command concurrent access
protection that was mistakenly removed on memory mapping operation
by commit e5620e0 ("drivers: flash: stm32 xspi flash read with
memcopy when executing").

Signed-off-by: Etienne Carriere <[email protected]>

Author: etienne-lms

drivers/flash/flash_stm32_xspi.c

@@ -1206,7 +1206,10 @@ static int flash_stm32_xspi_read(const struct device *dev, off_t addr,
 
 	/* Do reads through memory-mapping instead of indirect */
 	if (!stm32_xspi_is_memorymap(dev)) {
+		xspi_lock_thread(dev);
 		ret = stm32_xspi_set_memorymap(dev);
+		xspi_unlock_thread(dev);
+
 		if (ret != 0) {
 			LOG_ERR("READ: failed to set memory mapped");
 			return ret;