serial: qcom_geni: Comment use of devm_krealloc rather than devm_krealloc_array

Now that devm_krealloc_array is available, add a comment justifying not
changing this occurrence to avoid any future auto fixups.

Link: https://lore.kernel.org/all/20230318173402.20a4f60d@jic23-huawei/
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230509094942.396150-5-james.clark@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: James-A-Clark

drivers/tty/serial/qcom_geni_serial.c

@@ -1053,6 +1053,11 @@ static int setup_fifos(struct qcom_geni_serial_port *port)
 		(port->tx_fifo_depth * port->tx_fifo_width) / BITS_PER_BYTE;
 
 	if (port->rx_buf && (old_rx_fifo_depth != port->rx_fifo_depth) && port->rx_fifo_depth) {
+		/*
+		 * Use krealloc rather than krealloc_array because rx_buf is
+		 * accessed as 1 byte entries as well as 4 byte entries so it's
+		 * not necessarily an array.
+		 */
 		port->rx_buf = devm_krealloc(uport->dev, port->rx_buf,
 					     port->rx_fifo_depth * sizeof(u32),
 					     GFP_KERNEL);