can: mcp251x: Fix up includes

This driver is including the legacy GPIO header <linux/gpio.h>
but the only thing it is using from that header is the wrong
define for GPIOF_DIR_OUT.

Fix it up by using GPIO_LINE_DIRECTION_* macros respectively.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20240412173332.186685-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>