Fix a parentheses error in op_utf8_to_utf16().
Fix a parentheses error in op_utf8_to_utf16().

For many Latin1 characters this still worked correctly by pure luck.
Unfortunately, that included my test case.

SmartWalkieOrg/opusfile,gcp/opusfile,xiph/opusfile,gcp/opusfile,youfearm3/opusfile,xiph/opusfile,gcp/opusfile,SmartWalkieOrg/opusfile,xiph/opusfile,SmartWalkieOrg/opusfile,youfearm3/opusfile