Update secure boot UI driver to handle “reset to default” hot key.
Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Yao Jiewen <jiewen.yao@intel.com>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14257 6f19259b-4bc3-4df7-8a09-765794883524
Update SMM variable DXE driver GetNextVariable interface to comply with UEFI spec
VariableNameSize is the returned buffer size. GetNextVariable should behavior correct if it is bigger than SMM communication buffer or less than string size of VariableName. 

Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by  : Dong Guo   <guo.dong@intel.com>
Reviewed-by  : Fu Siyuan  <siyuan.fu@intel.com>
Reviewed-by  : Zeng Star  <star.zeng@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14258 6f19259b-4bc3-4df7-8a09-765794883524