can: mcp251xfd: mcp251xfd_chip_timestamp_init(): factor out into separate function

This patch factors out the timestamp initialization from the clock
initialization.

This is a preparation patch for the PLL support, where clock and
timestamp init must be done separately.

Link: https://lore.kernel.org/all/20220207131047.282110-11-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

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

@@ -421,6 +421,11 @@ static int mcp251xfd_chip_clock_init(const struct mcp251xfd_priv *priv)
 	if (err)
 		return err;
 
+	return 0;
+}
+
+static int mcp251xfd_chip_timestamp_init(const struct mcp251xfd_priv *priv)
+{
 	/* Set Time Base Counter Prescaler to 1.
 	 *
 	 * This means an overflow of the 32 bit Time Base Counter
@@ -683,6 +688,10 @@ static int mcp251xfd_chip_start(struct mcp251xfd_priv *priv)
 	if (err)
 		goto out_chip_stop;
 
+	err = mcp251xfd_chip_timestamp_init(priv);
+	if (err)
+		goto out_chip_stop;
+
 	err = mcp251xfd_set_bittiming(priv);
 	if (err)
 		goto out_chip_stop;