hwc: Move aspect ratio helper function to qdutils

Move aspect ratio helper function to qdutils so it can be used
as a utility function in libvirtual and libexternal without
introducing a circular dependency.

Change-Id: Ib295c1d9f78bc8898b1aac9a443cdacf53150551
diff --git a/libqdutils/qd_utils.h b/libqdutils/qd_utils.h
index db6d367..a35f255 100644
--- a/libqdutils/qd_utils.h
+++ b/libqdutils/qd_utils.h
@@ -48,4 +48,7 @@
 
 int getEdidRawData(char *buffer);
 
+void getAspectRatioPosition(int destWidth, int destHeight, int srcWidth,
+                                int srcHeight, hwc_rect_t& rect);
+
 #endif