OMAPDSS: Correct DISPC_IRQ bit definitions for LCD3

The DISPC_IRQ bit definitions pertaining to channel LCD3 as DISPC_IRQ_VSYNC3,
DISPC_IRQ_SYNC_LOST3, DISPC_IRQ_ACBIAS_COUNT_STAT3 AND DISPC_IRQ_FRAMEDONE3
which were incorrectly set in previous LCD3 patches have been corrected here.

Reported-by: Mark Tyler <mark.tyler@ti.com>
Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>