disp: msm: sde: reduce the latency in MDSS IRQ processing

Reduce the MDSS IRQ processing latency by skipping the status
register read/write of the interrupts which are not enabled.

Change-Id: Id86057ad3ab043ad76d4d4b44a373eff3b55da4d
Signed-off-by: Shirisha Kollapuram <[email protected]>

msm/sde/sde_hw_interrupts.c

@@ -446,6 +446,10 @@ static void sde_hw_intr_dispatch_irq(struct sde_hw_intr *intr,
 				end_idx > intr->sde_irq_map_size)
 			continue;
 
+		/* Skip the interrupts which are not enabled */
+		 if (!intr->cache_irq_mask[reg_idx])
+			continue;
+
 		/* Read interrupt status */
 		irq_status = SDE_REG_READ(&intr->hw, intr->sde_irq_tbl[reg_idx].status_off);