hwmon: (nct6775) Fix names of DIMM temperature sources

[ Upstream commit 3be8c9d103534fadc72b3e174613f37aa19fa423 ]

For NCT6795D and NCT6796D, the DIMM temperature sources are named
"Agent[01] Dimm [01]" per datasheet. Match names in datasheets to
avoid confusion.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>