drivers: can: mcan: use per-instance message RAM configuration

Restructure the Bosch M_CAN driver backend to use per-instance Message RAM
configuration.

This removes the need for a common, artificial "can" devicetree node for
SoCs with multiple Bosch M_CAN-based CAN controllers and allows for
per-instance configuration of the number of e.g. standard (11-bit) and
extended (29-bit) filter elements.

As part of the restructure, software handling of CAN filter flags was moved
from per-flags bitfields to per-filter bitfields, solving an issue when
using more than 32 standard (11-bit) filter elements or more than 16
extended (29-bit) filter elements.

Fixes: #42030, #53417

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>