include: drivers: mipi_dbi: document return value for mipi_dbi_release

Add documentation for possible return codes of mipi_dbi_release.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
diff --git a/include/zephyr/drivers/mipi_dbi.h b/include/zephyr/drivers/mipi_dbi.h
index d8f7c3b..d6ffcaf 100644
--- a/include/zephyr/drivers/mipi_dbi.h
+++ b/include/zephyr/drivers/mipi_dbi.h
@@ -276,6 +276,10 @@
  * locked.
  * @param dev mipi dbi controller
  * @param config MIPI DBI configuration
+ * @retval 0 reset succeeded
+ * @retval -EIO I/O error
+ * @retval -ENOSYS not implemented
+ * @retval -ENOTSUP not supported
  */
 static inline int mipi_dbi_release(const struct device *dev,
 				   const struct mipi_dbi_config *config)