bo_rockchip/_exynos: only set handle if newly created bo is non-NULL

Avoids a crash when .bo_create fails.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>

BUG=chrome-os-partner:37811
TEST=sanity check peach & veyron UI
  => There is no known repro for the original crash.

Change-Id: I20de8178e09cf658af864616af43672fe83c1002
Reviewed-on: https://chromium-review.googlesource.com/259620
Reviewed-by: Dominik Behr <dbehr@chromium.org>
Commit-Queue: Daniel Kurtz <djkurtz@chromium.org>
Trybot-Ready: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>
2 files changed