RuntimeDxe is used to back the runtime services time functions,
so align the description of the function return values with the
defined values for these services as described in UEFI Spec 2.10.
REF: UEFI spec 2.10 section 8 Services ? Runtime Services
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Signed-off-by: Suqiang Ren <suqiangx.ren@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>