Add the description of CapsuleImageSize to align with UEFI spec 2.10. REF: UEFI spec 2.10 section 8.5.3.1 Signed-off-by: Suqiang Ren <suqiangx.ren@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Liming Gao <gaoliming@byosoft.com.cn> Cc: Zhiguang Liu <zhiguang.liu@intel.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn> Reviewed-by: Felix Polyudov <felixp@ami.com>