hwc/overlay: Get rot dest dimensions instead of manipulating source

Currently for Mdss rotator we manipulate the layer buffer dimensions
to be equal to what rotator's destination dimensions would be, so that
these could be fed to MDP. Instead, this patch introduces APIs in
rotator so that hwc can directly query destination crop, width, height,
format from rotator.

This also simplifies the updateSource() and configRotator() helpers.

Change-Id: I501d998f2e0574683c764af9422742b2426ba0c7
diff --git a/liboverlay/overlayUtils.h b/liboverlay/overlayUtils.h
index 2fcc4ef..530377b 100644
--- a/liboverlay/overlayUtils.h
+++ b/liboverlay/overlayUtils.h
@@ -543,6 +543,14 @@
         value--;
 }
 
+/* Prerotation adjusts crop co-ordinates to the new transformed values within
+ * destination buffer. This is necessary only when the entire buffer is rotated
+ * irrespective of crop (A-family). If only the crop portion of the buffer is
+ * rotated into a destination buffer matching the size of crop, we don't need to
+ * use this helper (B-family).
+ * @Deprecated as of now, retained for the case where a full buffer needs
+ * transform and also as a reference.
+ */
 void preRotateSource(const eTransform& tr, Whf& whf, Dim& srcCrop);
 void getDump(char *buf, size_t len, const char *prefix, const mdp_overlay& ov);
 void getDump(char *buf, size_t len, const char *prefix, const msmfb_img& ov);