platform/x86: Introduce support for Mellanox hotplug driver

Enable system support for the Mellanox Technologies hotplug platform
driver, which provides support for the next Mellanox basic systems:
"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410",
"msb7800", "msn2740", "msn2100" and also various number of derivative
systems from the above basic types.
This driver handles hot-plug events for the power suppliers, power
cables and fans for the above systems.

The Kconfig currently controlling compilation of this code is:
driver/platform/x86:config MLX_CPLD_PLATFORM
                       tristate "Mellanox platform hotplug driver support"

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>