weston: modify display enable api [1/1]

PD#SWPL-185334

Problem:
weston crash when resume from light sleep.
repaint status not correct

Solution:
we need start repaint loop only when repaint is
not scheduled.

Verify:
t5w

Change-Id: I3a13feb11f515ba62ed4fa5b87f266210d9e4c67
Signed-off-by: limin.tian <limin.tian@amlogic.com>
diff --git a/aml-weston/aml-backend.c b/aml-weston/aml-backend.c
index 4c89a83..3fa32ec 100644
--- a/aml-weston/aml-backend.c
+++ b/aml-weston/aml-backend.c
@@ -1106,8 +1106,10 @@
 							wst_mode, output->base.current_scale);
 #endif
 			if (output->base.start_repaint_loop) {
-				output->base.repaint_status = REPAINT_AWAITING_COMPLETION;
-				output->base.start_repaint_loop(&output->base);
+				if (output->base.repaint_status == REPAINT_NOT_SCHEDULED) {
+					output->base.repaint_status = REPAINT_AWAITING_COMPLETION;
+					output->base.start_repaint_loop(&output->base);
+				}
 			}
 		}
 	} else if (enable == 0) {