hwmon: (amc6821) add of_match table

Add of_match table for "ti,amc6821" compatible string.
This fixes automatic driver loading by userspace when using device-tree,
and if built as a module like major linux distributions do.

While devices probe just fine with i2c_device_id table, userspace can't
match the "ti,amc6821" compatible string from dt with the plain
"amc6821" device id. As a result, the kernel module can not be loaded.

Cc: stable@vger.kernel.org
Signed-off-by: Josua Mayer <josua@solid-run.com>
Link: https://lore.kernel.org/r/20240307-amc6821-of-match-v1-1-5f40464a3110@solid-run.com


[groeck: Cleaned up patch description]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>