Range.java:Correct sign error in description

Current description for android.util.Range says ""All ranges are bounded, and the left side of the
range is always {@code >=} * the right side of the range." It should have been  "<=" there instead
of ">=".  So, corrected that in this CL.

Bug: 122271254

Test: make offline-sdk-docs
      Modified description was visible correctly.

Change-Id: I1eaa94210b39813b3e72ac2a0834bc0b466a99a5