power_supply: Fix duplicate variant value

mapbox::variant is fine with having a variant contain duplicate types.
However std::variant thrips a static assert if you duplicate the types
contained in the variant. This is just a refactor that will not affect
behavior.

Tested:
    Compiled and run through unit tests.

Change-Id: I99628f8f520ff58df35eee1d51772b0e93f2d9fd
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/power-supply/power_supply.cpp b/power-supply/power_supply.cpp
index 1c069d1..62827ed 100644
--- a/power-supply/power_supply.cpp
+++ b/power-supply/power_supply.cpp
@@ -209,8 +209,7 @@
 {
     int32_t state = 0;
     std::string msgSensor;
-    std::map<std::string, sdbusplus::message::variant<int32_t, int32_t>>
-        msgData;
+    std::map<std::string, sdbusplus::message::variant<int32_t>> msgData;
     msg.read(msgSensor, msgData);
 
     // Check if it was the Present property that changed.