can: c_can: Add support for Bosch D_CAN controller

This patch adds the support for D_CAN controller driver to the existing
C_CAN driver.

Bosch D_CAN controller is a full-CAN implementation which is compliant
to CAN protocol version 2.0 part A and B. Bosch D_CAN user manual can be
obtained from: http://www.semiconductors.bosch.de/media/en/pdf/
ipmodules_1/can/d_can_users_manual_111.pdf

A new array is added for accessing the d_can registers, according to d_can
controller register space.

Current D_CAN implementation has following limitations, this is done
to avoid large changes to the C_CAN driver.
1. Message objects are limited to 32, 16 for RX and 16 for TX. C_CAN IP
   supports upto 32 message objects but in case of D_CAN we can configure
   upto 128 message objects.
2. Using two 16bit reads/writes for accessing the 32bit D_CAN registers.
3. These patches have been tested on little endian machine, there might
   be some hidden endian-related issues due to the nature of the accesses
   (32-bit registers accessed as 2 16-bit registers). However, I do not
   have a big-endian D_CAN implementation to confirm.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>