Since PcdHiiOsRuntimeSupport has added in the MdeModulePkg.dec file,
now add the usage information in the uni file.
Cc: Qiu Shumin <shumin.qiu@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Qiu Shumin <shumin.qiu@intel.com>