drivers: can: mcan: use __nocache_noinit for MRAM data variables

Use __nocache_noinit for the Bosch M_CAN MRAM data variables on SoCs
without dedicated MRAM.

Fixes: #64691

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
(cherry picked from commit 58e1963c)