Do not fix line endings for binary image files

Change-Id: Ib9270d64b9bd53de3694c2b96f26b18dc21f70f0
Issue-ID: INT-748
Signed-off-by: Gary Wu <gary.i.wu@huawei.com>
diff --git a/.gitattributes b/.gitattributes
index 6313b56..3185c44 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1 +1,4 @@
 * text=auto eol=lf
+*.png binary
+*.jpg binary
+*.xlsx binary