DRM: Armada: Add support for ARGB 32x64 or 64x32 hardware cursors

This patch adds ARGB hardware cursor support to the DRM driver for the
Marvell Armada SoCs.  ARGB cursors are supported at either 32x64 or
64x32 resolutions.

Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>