linux-imx

can: mcp251x: remove custom DMA mapped buffer

There is no need to duplicate what SPI core already does, i.e. mapping buffers
for DMA capable transfers. This patch removes all related pices of code.

Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>