hwc: Add support for YCrCb_420_SP_VENUS(NV21_VENUS)

* Earlier, camera preview buffers were of NV21(YCrCb_420_SP)
  and the video buffers were of NV12_VENUS(YCbCr_420_SP_VENUS)
  format. Now that the video encoder has support for NV21,
  both the camera and video buffers can be of
  NV21_VENUS(YCrCb_420_SP_VENUS) format.

* If the preview and video buffer sizes are the same,
  CPP double pass to generate video and preview buffers can be
  avoided and the buffers can now be generated within a single pass
  with CPP duplication thereby saving power.

* Add support in gralloc for NV12_VENUS format to achieve
  the same.

Change-Id: I7001f975f2cafa21c893e7384ddbddd5f2788b1d
diff --git a/libhwcomposer/hwc_dump_layers.cpp b/libhwcomposer/hwc_dump_layers.cpp
index aad984d..fca8a5c 100644
--- a/libhwcomposer/hwc_dump_layers.cpp
+++ b/libhwcomposer/hwc_dump_layers.cpp
@@ -448,6 +448,9 @@
         case HAL_PIXEL_FORMAT_YCbCr_420_SP_VENUS:
             strlcpy(pixFormatStr, "YCbCr_420_SP_VENUS", sizeof(pixFormatStr));
             break;
+        case HAL_PIXEL_FORMAT_YCrCb_420_SP_VENUS:
+            strlcpy(pixFormatStr, "YCrCb_420_SP_VENUS", sizeof(pixFormatStr));
+            break;
         default:
             size_t len = sizeof(pixFormatStr);
             snprintf(pixFormatStr, len, "Unknown0x%X", format);