Add AID_SDCARD_R.

Change-Id: I47f650e415e06c0b69790ffefea7f208c910ebd7
diff --git a/include/private/android_filesystem_config.h b/include/private/android_filesystem_config.h
index 0344b5c..a3d5e62 100644
--- a/include/private/android_filesystem_config.h
+++ b/include/private/android_filesystem_config.h
@@ -61,6 +61,7 @@
 #define AID_UNUSED2       1025  /* deprecated, DO NOT USE */
 #define AID_DRMRPC        1026  /* group for drm rpc */
 #define AID_NFC           1027  /* nfc subsystem */
+#define AID_SDCARD_R      1028  /* external storage read access */
 
 #define AID_SHELL         2000  /* adb and debug shell user */
 #define AID_CACHE         2001  /* cache access */