src/dst rects are checked in both atomic_check and atomic_update, with
the more comprehensive check occurring in atomic_update, which is
backwards. So consolodate the checks in atomic_check.

Changes in v2:
- Use the correct crtc state (Jeykumar)

Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
Reviewed-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>