Fix threshold conversion

Converting to float first makes the values get extra
garbage data. Go directly to double.

Change-Id: I1c4af05d89e6adcabcf1a3b1bef523c61c0515fd
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/src/Thresholds.cpp b/src/Thresholds.cpp
index 653b4e6..36556cf 100644
--- a/src/Thresholds.cpp
+++ b/src/Thresholds.cpp
@@ -98,7 +98,7 @@
         {
             direction = Direction::HIGH;
         }
-        float val = std::visit(VariantToFloatVisitor(), valueFind->second);
+        double val = std::visit(VariantToDoubleVisitor(), valueFind->second);
 
         thresholdVector.emplace_back(level, direction, val);
     }