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>
diff --git a/src/bo_exynos.c b/src/bo_exynos.c
index 93604fe..13b54bf 100644
--- a/src/bo_exynos.c
+++ b/src/bo_exynos.c
@@ -64,6 +64,9 @@
 	flags |= EXYNOS_BO_NONCONTIG;
 
 	exynos_bo = exynos_bo_create(dev->bo_dev, size, flags);
+	if (!exynos_bo)
+		return NULL;
+
 	*handle = exynos_bo_handle(exynos_bo);
 
 	return exynos_bo;
diff --git a/src/bo_rockchip.c b/src/bo_rockchip.c
index 1b77119..320e22e 100644
--- a/src/bo_rockchip.c
+++ b/src/bo_rockchip.c
@@ -62,6 +62,9 @@
 	struct rockchip_bo *rockchip_bo;
 
 	rockchip_bo = rockchip_bo_create(dev->bo_dev, size, flags);
+	if (!rockchip_bo)
+		return NULL;
+
 	*handle = rockchip_bo_handle(rockchip_bo);
 
 	return rockchip_bo;