can: mcp251x: simplify with spi_get_device_match_data()

Use spi_get_device_match_data() helper to simplify a bit the driver.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/all/20240606142424.129709-2-krzysztof.kozlowski@linaro.org


[mkl: add intermediate cast to uintptr_t]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>