mdp4_overlay: Fix glitches while using MDP composition

This fixes this error:
[   70.664855] mdp_enable_irq: MDP IRQ term-0x1 is already set, mask=1 irq=1

Pulled from stock Samsung JB kernel source.

Signed-off-by: Sultanxda <sultanxda@gmail.com>
Sultan_defconfig: v1.3.5