video: Fix double cropping source/output region of tdm

video: Fix double cropping source/output region of tdm

Cropping an already cropped source/output region is an error.
So, this change makes updating tdm config happen once during render job.

So far this has been no problem since wl_client didn't try to set its
output region beyond the screen. However, once wl_client tried to do
that, the problem came out because of the double cropping.

More specifically, source region was a problem. source region was
cropped and updated once during applying viewport, but it was cropped
and updated again with already cropped source region during applying
map.

Change-Id: Ia8efb27a3af66eda5564f166a9ea734d21a93cf1