Add bios post checking support

Some sensors aren't available until after bios post
add support to check for post when needed.

Tested-by: SSB temp no longer asserted thresholds before
bios post.

Change-Id: I9251c2c501e082ef4bb0e9eb7909dc137771e120
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/src/ADCSensorMain.cpp b/src/ADCSensorMain.cpp
index 9474caa..7f7f812 100644
--- a/src/ADCSensorMain.cpp
+++ b/src/ADCSensorMain.cpp
@@ -211,10 +211,7 @@
         {
             std::string powerState = variant_ns::visit(VariantToStringVisitor(),
                                                        findPowerOn->second);
-            if (powerState == "On")
-            {
-                readState = PowerState::on;
-            };
+            setReadState(powerState, readState);
         }
 
         sensors[sensorName] = std::make_unique<ADCSensor>(