drm/amd/display: Use non-deprecated vblank handler

[Why]
drm_handle_vblank is deprecated. Use drm_crtc_handle_vblank instead.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: David Francis <David.Francis@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>