Allow batteryChargeTimeToFullNowSeconds to be -1

Test: Run the test under an implementation that doesn't support
  batteryChargeTimeToFullNowSeconds
Bug: 166841711
Change-Id: I18fb11bb0a2233a9a89183a5f9ecf597e7719172
diff --git a/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp b/health/2.1/vts/functional/VtsHalHealthV2_1TargetTest.cpp
index 43e6cdc..d0b0d60 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";