hwc: Add support for RGBA_4444 and RGBA_5551 formats

1. Modify gralloc library to allocate buffers for RGBA_4444 and
   RGBA_5551 formats
2. Modify copybit library to add composition support for RGBA_4444
   and RGBA_5551 layers
3. Modify hwc library to add MDP composition and rotator support for
   RGBA_4444 and RGBA_5551 layers.

Change-Id: I30dbc4e5e2c010835fa7e7663f996f67779a1803
diff --git a/libhwcomposer/hwc_utils.cpp b/libhwcomposer/hwc_utils.cpp
index 3357920..6a74625 100644
--- a/libhwcomposer/hwc_utils.cpp
+++ b/libhwcomposer/hwc_utils.cpp
@@ -1154,6 +1154,8 @@
     if(hnd != NULL) {
         switch(hnd->format) {
             case HAL_PIXEL_FORMAT_RGBA_8888:
+            case HAL_PIXEL_FORMAT_RGBA_5551:
+            case HAL_PIXEL_FORMAT_RGBA_4444:
             case HAL_PIXEL_FORMAT_RGB_565:
             case HAL_PIXEL_FORMAT_RGB_888:
             case HAL_PIXEL_FORMAT_BGRA_8888: