drm: omapdrm: Use unsigned int type

The kernel favours 'unsigned int' over plain 'unsigned'. Replace all
occurences of the latter by the former. This avoid lots of checkpatch
complaints in patches that touch lines where a plain 'unsigned' is used.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>