hwmon: (lm90) Mention support for TI TMP451 in Kconfig description

The lm90 driver also supports the Texas Instruments TMP451 sensor chip.
Since the Kconfig description for the driver includes a list of all
compatible chips, mention the TI TMP451 there as well.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>