docs: hwmon: (amd_energy) update documentation

Update the supported processors and mention vulnerability fix.

Signed-off-by: Naveen Krishna Chatradhi <NaveenKrishna.Chatradhi@amd.com>
Link: https://lore.kernel.org/r/20201119184246.228322-2-NaveenKrishna.Chatradhi@amd.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>