libhardware: add support for tertiary display

The legacy HWC header only supports Primary and External, we need
to support Tertiary display for automotive project.

Change-Id: I37637bf6c3ec341b9174a9f488b8bf06e0011733
diff --git a/include/hardware/hwcomposer_defs.h b/include/hardware/hwcomposer_defs.h
index e650bd2..0131bc5 100644
--- a/include/hardware/hwcomposer_defs.h
+++ b/include/hardware/hwcomposer_defs.h
@@ -203,15 +203,17 @@
 enum {
     HWC_DISPLAY_PRIMARY     = 0,
     HWC_DISPLAY_EXTERNAL    = 1,    // HDMI, DP, etc.
-    HWC_DISPLAY_VIRTUAL     = 2,
+    HWC_DISPLAY_TERTIARY    = 2,
+    HWC_DISPLAY_VIRTUAL     = 3,
 
-    HWC_NUM_PHYSICAL_DISPLAY_TYPES = 2,
-    HWC_NUM_DISPLAY_TYPES          = 3,
+    HWC_NUM_PHYSICAL_DISPLAY_TYPES = 3,
+    HWC_NUM_DISPLAY_TYPES          = 4,
 };
 
 enum {
     HWC_DISPLAY_PRIMARY_BIT     = 1 << HWC_DISPLAY_PRIMARY,
     HWC_DISPLAY_EXTERNAL_BIT    = 1 << HWC_DISPLAY_EXTERNAL,
+    HWC_DISPLAY_TERTIARY_BIT    = 1 << HWC_DISPLAY_TERTIARY,
     HWC_DISPLAY_VIRTUAL_BIT     = 1 << HWC_DISPLAY_VIRTUAL,
 };