ivi-shell: Set view mask solely based on source rectangle

Controller application sets the source and destination rectangles for any surface. Based on these parameters configure event is sent to the client application. Currently view mask is capped to the current buffer dimensions of the client. This will not work in a use case where client configures its buffer size based on configure notification from ivi-shell and the new buffer size is larger. In such a case view mask will be of smaller dimension compared to the client buffer and it results in un-desired clipping of client buffer.

To resolve this, use source rectangle as view mask. weston will take care to clip the boundingbox of view to client buffer dimension if the client buffer is smaller.

Signed-off-by: Harsha M M harsha.manjulamallikarjun@in.bosch.com