platform_data/mlxreg: Add new type to support modular systems

platform_data/mlxreg: Add new type to support modular systems

Add new types for the Nvidia modular systems MSN4800 which could
be equipped with the different types of replaceable line cards.

Add new type to specify the kind of hotplug events for the line cards.
The line card events are generated by the programmable device located
on the main board. This device implements interrupt controller logic.
Line card interrupts are associated with different line cards states
during its initialization: insertion, security signature validation,
power good state, security validation, hardware-firmware
synchronization state, line card PHYs readiness state, firmware
availability for line card ports. Also under some circumstances
hardware can generate thermal shutdown for particular line card.

Add new type specifying the action, which should be performed when
particular hotplug event is received. This action defines in which way
hotplug event should be handled by hotplug driver. There are the next
actions types:
- Connect I2C device with empty 'platform_data' field according to the
  platform topology, if device is configured (for example, power unit
  micro-controller driver, when power unit is connected to power source
  (this is what is currently supported).
- Connect device with 'platform_data' field set according to the
  platform topology. The purpose is to pass 'platform_data' through
  hotplug driver to underlying device (for example line card driver).
- No device is associated with hotplug event - just send "udev" event
 (this is what is currently supported).

Extend structure 'mlxreg_hotplug_device' with hotplug action field.

Extend structure 'mlxreg_core_data' with:
- Registers for line card power and enabling control.
- Slot number field, to indicate at which physical slot replaceable
  line card device is located.

Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Michael Shych <michaelsh@nvidia.com>
Link: https://lore.kernel.org/r/20211002093238.3771419-2-vadimp@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>