drm/core: Do not call drm_framebuffer_remove internally during teardown.

This may cause issues because encoders are already destroyed so removing
active primaries may use freed memory. Instead free the fb directly,
ignoring refcount.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>