platform/x86: mlx-platform: Add mlxreg-io platform driver activation

Add mlxreg-io platform driver activation. Access driver uses the same
regmap infrastructure as others Mellanox platform drivers.
Specific registers description for default platform data configuration are
added to mlx-platform. There are the registers for resets control, reset
causes monitoring, programmable devices version reading and mux select
control. This platform data is passed to mlxreg-io driver. Also some
default values for the register are set at initialization time through
the regmap infrastructure, which are necessary for moving write protection
from the general purpose registers, which are used by mlxreg-io for
write access.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
v4-v5:
 Changes added by Vadim:
 - Add two new attributes for ASIC health and main power domain shutdown.
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>