improve hwc dumpsys

we now log the buffer's format

Change-Id: I9d3ad8018e884240a153de3baefb6331cb014d0f
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index df13640..431cd1a 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -925,7 +925,7 @@
             // what's happening here is tricky.
             // we want to clear all the layers with the CLEAR_FB flags
             // that are opaque.
-            // however, since some GPU have are efficient at preserving
+            // however, since some GPU are efficient at preserving
             // the backbuffer, we want to take advantage of that so we do the
             // clear only in the dirty region (other areas will be preserved
             // on those GPUs).