tests: fix memory leak issue

Fixed memory leak issue to drmModeRes and drmModePlaneRes objects.

These objects were allocated by drmModeGetResources and
drmModeGetPlaneResources functions but not freed properly.

So this patch frees them by calling drmModeFreeResources
drmModeFreePlaneResources functions at failure case.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>