can: mcp251x: Use dmam_alloc_coherent

This patch moves the data allocated using dma_alloc_coherent to the
corresponding managed interface and does away with the calls to free the
allocated memory in the probe and remove functions.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>