[Feature][ZXW-88]merge P50 version

Only Configure: No
Affected branch: master
Affected module: unknown
Is it affected on both ZXIC and MTK: only ZXIC
Self-test: Yes
Doc Update: No

Change-Id: I34667719d9e0e7e29e8e4368848601cde0a48408
diff --git a/ap/lib/libpng/libpng-1.6.37/tests/pngstest-linear b/ap/lib/libpng/libpng-1.6.37/tests/pngstest-linear
new file mode 100755
index 0000000..4a5b3fe
--- /dev/null
+++ b/ap/lib/libpng/libpng-1.6.37/tests/pngstest-linear
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" linear none