audio: compress error propagation

- On compress error, error type is not
  propagating from compress driver

- Modify oops API to return error no

Change-Id: I51031e96f1fa8838b51fffda64730a05c708cf4e
diff --git a/compress.c b/compress.c
index 83b041b..091fc3a 100644
--- a/compress.c
+++ b/compress.c
@@ -107,7 +107,7 @@
 		": %s", strerror(e));
 	errno = e;
 
-	return -1;
+	return -errno;
 }
 
 const char *compress_get_error(struct compress *compress)