hwmon: (it87) Updated documentation for recent updates to it87

Updated the driver documentation to list all current chips and
describe the module parameters as per descriptions in the code.

Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230128060308.1549707-8-frank@crawford.emu.id.au
Signed-off-by: Guenter Roeck <linux@roeck-us.net>