Use BoringSSL to get random bytes

Bug: 117508900
Change-Id: I4889513c0671ff2b689f1beca8084d6f149d473d
Test: Existing tests pass
diff --git a/wpa_supplicant/Android.mk b/wpa_supplicant/Android.mk
index 4ca4281..dbf493c 100644
--- a/wpa_supplicant/Android.mk
+++ b/wpa_supplicant/Android.mk
@@ -969,6 +969,7 @@
 
 ifndef CONFIG_TLS
 CONFIG_TLS=openssl
+L_CFLAGS += -DCONFIG_USE_OPENSSL_RNG
 endif
 
 ifdef CONFIG_TLSV11