drm/amd/display: Clear MASTER_UPDATE_LOCK_DB_EN when disable doublebuffer lock

[Why]
It seems there's a typo to set MASTER_UPDATE_LOCK_DB_EN when disable
doublebuffer lock.

[How]
Clear MASTER_UPDATE_LOCK_DB_EN when disable doublebuffer lock
Signed-off-by: Robin Chen <robin.chen@amd.com>
Reviewed-by: Joshua Aberback <Joshua.Aberback@amd.com>
Acked-by: Wayne Lin <waynelin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_optc.c

@@ -97,7 +97,7 @@ void optc3_lock_doublebuffer_disable(struct timing_generator *optc)
 		MASTER_UPDATE_LOCK_DB_END_Y, 0);
 
 	REG_UPDATE(OTG_GLOBAL_CONTROL2, GLOBAL_UPDATE_LOCK_EN, 0);
-	REG_UPDATE(OTG_GLOBAL_CONTROL0, MASTER_UPDATE_LOCK_DB_EN, 1);
+	REG_UPDATE(OTG_GLOBAL_CONTROL0, MASTER_UPDATE_LOCK_DB_EN, 0);
 }
 
 void optc3_lock(struct timing_generator *optc)