can: mcp251xfd: mcp251xfd_chip_stop(): convert to a void function

The mcp251xfd_chip_stop() function tries the best to stop the chip and
put it into sleep mode. It continues, even if some intermediate steps
fail. As none of the callers use the return value, let this function
return void.

Link: https://lore.kernel.org/all/20220207131047.282110-6-mkl@pengutronix.deSigned-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

@@ -633,14 +633,14 @@ static int mcp251xfd_chip_interrupts_disable(const struct mcp251xfd_priv *priv)
 	return regmap_write(priv->map_reg, MCP251XFD_REG_CRC, 0);
 }
 
-static int mcp251xfd_chip_stop(struct mcp251xfd_priv *priv,
-			       const enum can_state state)
+static void mcp251xfd_chip_stop(struct mcp251xfd_priv *priv,
+				const enum can_state state)
 {
 	priv->can.state = state;
 
 	mcp251xfd_chip_interrupts_disable(priv);
 	mcp251xfd_chip_rx_int_disable(priv);
-	return mcp251xfd_chip_sleep(priv);
+	mcp251xfd_chip_sleep(priv);
 }
 
 static int mcp251xfd_chip_start(struct mcp251xfd_priv *priv)