hwc/copybit: Handle "R/B swap" for RGBA and RGBX color formats.

1.Framework notifies HAL with "HWC_FORMAT_RB_SWAP" layer flag to handle
a limitation where R and B components were swapped in Rendering phase.
2.Add "R/B swap" in hwc query to enable framework to query for support
in display HAL, at run-time.

Change-Id: I3b44d15b51b4f24939048fee9d1bac2b9009c97c
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 3b5d3cb..8fb62a0 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -127,6 +127,11 @@
     HWC_COPYBIT = 0x00000002,
 };
 
+// HAL specific features
+enum {
+    HWC_FORMAT_RB_SWAP = 0x00000040,
+};
+
 class LayerRotMap {
 public:
     LayerRotMap() { reset(); }