sdm : Reset cached auto_refresh_ variable during suspend.

Reset auto_refresh_ variable to avoid inconsistency between
driver and HAL.

Change-Id: I0baba5ac11e808a85944ebe87fe918c9894e4e9f
CRs-Fixed: 1074788
diff --git a/sdm/libs/core/fb/hw_primary.cpp b/sdm/libs/core/fb/hw_primary.cpp
index f3c7639..3dfa4dd 100644
--- a/sdm/libs/core/fb/hw_primary.cpp
+++ b/sdm/libs/core/fb/hw_primary.cpp
@@ -332,6 +332,8 @@
     return kErrorHardware;
   }
 
+  auto_refresh_ = false;
+
   return kErrorNone;
 }