disp: msm: sde: expose early-wb-fence option for 2-pass composition

Add a writeback connector property EARLY-FENCE-LINE to give usermode
the control on when to trigger the retire fence. This option is useful
in 2-pass composition, where the writeback triggers the retire-fence
early based on the prog-line which allows primary to start the fetch
before wb transaction is fully completed. This helps to keep the clks
and bw low. WB hardware generates the line-ptr-irq when wb output reaches
the configured prog-line. Retire fence is triggered based on the irq by
default and wb-done handles for cases where line-ptr-irq is missed.

Change-Id: I20867979693dc3447f77da24cd7e88305947fb6d
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>

msm/msm_drv.h

@@ -218,6 +218,7 @@ enum msm_mdp_conn_property {
 	CONNECTOR_PROP_DYN_BIT_CLK,
 	CONNECTOR_PROP_DIMMING_CTRL,
 	CONNECTOR_PROP_DIMMING_MIN_BL,
+	CONNECTOR_PROP_EARLY_FENCE_LINE,
 
 	/* enum/bitmask properties */
 	CONNECTOR_PROP_TOPOLOGY_NAME,