Disable VABC xor if COW isn't compressed

XOR only saves space if COW data is compressed. If compression parameter
is set to none, disable XOR as it does not save anything but still costs
CPU cycles.

Test: th
Change-Id: I674ad74140570ce4740c290d1adb9e9b5a08426e

tools/releasetools/ota_from_target_files.py

@@ -894,6 +894,9 @@ def GenerateAbOtaPackage(target_file, output_file, source_file=None):
     logger.info("VABC XOR Not supported, disabling")
     OPTIONS.enable_vabc_xor = False
 
+  if OPTIONS.vabc_compression_param == "none":
+    logger.info("VABC Compression algorithm is set to 'none', disabling VABC xor")
+    OPTIONS.enable_vabc_xor = False
   additional_args = []
 
   # Prepare custom images.