Allow batteryChargeTimeToFullNowSeconds to be -1

Test: Run the test under an implementation that doesn't support
  batteryChargeTimeToFullNowSeconds
Bug: 166841711
Change-Id: I18fb11bb0a2233a9a89183a5f9ecf597e7719172
Merged-In: I18fb11bb0a2233a9a89183a5f9ecf597e7719172
(cherry picked from commit c2dc510a0aec6c88b370ab5f1eb41a7de1e64d67)
diff --git a/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp b/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp
index deb1a29..288df36 100644
--- a/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp
+++ b/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp
@@ -233,7 +233,7 @@
         ASSERT_EQ(Result::SUCCESS, result);
 
         EXPECT_TRUE(IsEnum(value.batteryCapacityLevel)) << " BatteryCapacityLevel";
-        EXPECT_GE(value.batteryChargeTimeToFullNowSeconds, 0);
+        EXPECT_GE(value.batteryChargeTimeToFullNowSeconds, -1);
 
         EXPECT_GE(value.batteryFullChargeDesignCapacityUah, 0)
                 << "batteryFullChargeDesignCapacityUah should not be negative";