Revert "HiKey/HiKey960: Set PRODUCT_SHIPPING_LEVEL to 29"

This reverts commit cc74a76a21b7e216063305bb1f966213a78aea4e.

Reason for revert: requires gatekeeper

Change-Id: If1ce02be1f21c4263a6eafc439619fe7f3f00e51
diff --git a/device-common.mk b/device-common.mk
index 6412d14..0b53f89 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -29,9 +29,18 @@
 # Set vendor kernel path
 PRODUCT_VENDOR_KERNEL_HEADERS := device/linaro/hikey/kernel-headers
 
-PRODUCT_SHIPPING_API_LEVEL := 29
-PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS := false
-
+# Hikey was first supported from Marshmallow 6.0, API level 23
+# PRODUCT_SHIPPING_API_LEVEL is required from Pie build by the CTS test of
+# CtsOsTestCases android.os.cts.BuildTest#testSdkInt
+# as reported here:
+# https://bugs.linaro.org/show_bug.cgi?id=4068
+# https://source.android.com/setup/start/build-numbers
+# Here we set it to 25 first, because Gatekeeper function
+# needs to be supported when set to 26 or above,
+# which we could not boot successfully with the default implementation
+# enabled yet. Will back to set it to the latest number when we have
+# all necessary features supported.
+PRODUCT_SHIPPING_API_LEVEL := 25
 
 # Set custom settings
 DEVICE_PACKAGE_OVERLAYS := device/linaro/hikey/overlay
diff --git a/manifest.xml b/manifest.xml
index 67d932b..f45676c 100644
--- a/manifest.xml
+++ b/manifest.xml
@@ -1,4 +1,4 @@
-<manifest version="1.0" type="device" target-level="2">
+<manifest version="1.0" type="device">
     <hal format="hidl">
         <name>android.hardware.audio</name>
         <transport>hwbinder</transport>