Extend the structure 'mlxreg_hotplug_device" with platform device field
to allow transition of the register map and system interrupt line number
to underlying hotplug devices, sharing the same register map and
same interrupt line with 'mlxreg-hotplug' driver.

Extend logic for hotplug devices creation and removing according to
the action associated with the hotplug device description. Previously
hotplug driver was capable to attach / de-attach upon hotplug events
only I2C devices handled by simple I2C drivers. Now it should be able
to attach also devices handled by the platform drivers.

The motivation is to allow transition of platform data like:
- system interrupt line number, sharing with 'mlxreg-hotplug' to
  underlying hotplug devices.
- shared register map of programmable devices on main board to
  underlying hotplug devices.

Additioanlly the number of 'sysfs' attributes is increased, since
modular system defines more 'sysfs' attributes.
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Michael Shych <michaelsh@nvidia.com>
Link: https://lore.kernel.org/r/20211002093238.3771419-4-vadimp@nvidia.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>