hwmon: (ltc2978) Add support for LTC2980 and LTM2987

LTC2980 and LTM2987 are command compatible to LTC2977. They consist of
two LTC2977 on a single die, and are instantiated as two separate chips,
each supporting eight channels.

Suggested-by: Michael Jones <mike@proclivis.com>
Tested-by: Michael Jones <mike@proclivis.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 8279727..af778ae 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -52,8 +52,8 @@
 	default n
 	help
 	  If you say yes here you get hardware monitoring support for Linear
-	  Technology LTC2974, LTC2975, LTC2977, LTC2978, LTC3880, LTC3883,
-	  LTC3887, and LTM4676.
+	  Technology LTC2974, LTC2975, LTC2977, LTC2978, LTC2980, LTC3880,
+	  LTC3883, LTC3887, LTCM2987, and LTM4676.
 
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc2978.