drm/omap: Use bitmaps for TILER placement

Modified Tiler placement to utilize bitmaps for bookkeeping and
all placement algorithms.  This resulted in a substantial savings
in time for all Tiler reservation and free operations.  Typical
savings are in the range of 28% decrease in time taken with larger
buffers showing a 80%+ decrease.

Signed-off-by: Andy Gross <andy.gross@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>