Allow system server to check if the mainline
supplicant binary exists.

Bug: 365585450
Test: Manual test - check if the binary exists
      from the Wifi mainline module
Change-Id: I18ccd5301c1a712b94f760b63a9b5d725c95fa53
diff --git a/private/system_server.te b/private/system_server.te
index 4e5112e..7bdcaef 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -700,6 +700,9 @@
 # Access to /data/media for measuring disk usage.
 allow system_server media_rw_data_file:dir { search getattr open read };
 
+# Access to check if the mainline supplicant binary exists
+allow system_server wifi_mainline_supplicant_exec:file getattr;
+
 # Receive and use open /data/media files passed over binder IPC.
 # Also used for measuring disk usage.
 allow system_server media_rw_data_file:file { getattr read write append };