Sync patch r14379 from main trunk.
Fix the TOCTOU issue of CommBufferSize itself for SMM communicate handler input.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/branches/UDK2010.SR1@14382 6f19259b-4bc3-4df7-8a09-765794883524
Check DHCP Server Binding protocol in Supported().

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/branches/UDK2010.SR1@14384 6f19259b-4bc3-4df7-8a09-765794883524