drm/amd/display: Add missing pflip irq

If we have more than 4 displays we will run
into dummy irq calls or flip timout issues.
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 5.9.x

drivers/gpu/drm/amd/display/dc/irq/dcn30/irq_service_dcn30.c

@@ -306,8 +306,8 @@ irq_source_info_dcn30[DAL_IRQ_SOURCES_NUMBER] = {
 	pflip_int_entry(1),
 	pflip_int_entry(2),
 	pflip_int_entry(3),
-	[DC_IRQ_SOURCE_PFLIP5] = dummy_irq_entry(),
-	[DC_IRQ_SOURCE_PFLIP6] = dummy_irq_entry(),
+	pflip_int_entry(4),
+	pflip_int_entry(5),
 	[DC_IRQ_SOURCE_PFLIP_UNDERLAY0] = dummy_irq_entry(),
 	gpio_pad_int_entry(0),
 	gpio_pad_int_entry(1),