mailbox: Pack SCPI structures used for messages.

The System Control Processor expects data sent in the messages
to be contiguos. When using unpacked structures to describe
the data being transmitted we increase the general size of the
message which leads to SCP rejecting our request.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
drm: hdlcd: Don't depend on VSYNC interrupt when setting new framebuffer.

VSYNC state is influenced by the DRM framework and cannot be relied
on when setting a new framebuffer base address and synchronising with
the hardware. Use the DMA_END interrupt as it is a more reliable way
of signaling the end of frame utilisation.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>