[Description]

[Description]
add a judgement of whether the control command is equal with previous one or not.
[Impaction]
Judge if the control command is equaled with previous one. This handler can improve performance.
[Reference Info]
Currently the terminal driver outputs control commands upon user's request regardless of whether the new attribute is the same as previous one or not.
Actually, it could be implemented as only outputting control command when the new Attribute is different than previous one

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5113 6f19259b-4bc3-4df7-8a09-765794883524