Fix a bug in motion search code(2)

This fix added MV range checks for NEWMV mode as suggested by Jim.
To reduce unnecessary MV range checks, I tried Yaowu's suggestion.
Update UMV borders in NEWMV mode to also cover MV range check.
Also, in this way, every MV that is valid gets checked in diamond
search function.

Change-Id: I95a89ce0daf6f178c454448f13d4249f19b30f3a