Allow wpa to perform binder IPC to keystore.

Addresses denials such as:
 avc:  denied  { call } for  pid=2275 comm="wpa_supplicant" scontext=u:r:wpa:s0 tcontext=u:r:servicemanager:s0 tclass=binder

Change-Id: I8ab148046dd06f56630a2876db787b293e14c0ae
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

wpa.te

@@ -17,6 +17,9 @@ allow wpa wifi_data_file:file create_file_perms;
 unix_socket_send(wpa, system_wpa, system_server)
 allow wpa random_device:chr_file r_file_perms;
 
+binder_use(wpa)
+binder_call(wpa, keystore)
+
 # Create a socket for receiving info from wpa
 type_transition wpa wifi_data_file:dir wpa_socket "sockets";
 allow wpa wpa_socket:dir create_dir_perms;