Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces

Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces

Add documentation for the new attributes for:
- Exposing reset causes types asserted by: platform reset, SoC reset,
  AC power failure, software power off request.
- Setting and removing system VPD (EEPROM) hardware write protection.
- Voltage regulator devices configuration update status and firmware
  version.
- Setting PCIe ASIC reset to disable or enable state during PCIe root
  complex reset.
- System static topology identification, like system's static I2C
  topology, number and type of FPGA devices within the system and so on.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>