[entropy_src/rtl] gate fifo_err

Signed-off-by: Mark Branstad <mark.branstad@wdc.com>
diff --git a/hw/ip/entropy_src/rtl/entropy_src_core.sv b/hw/ip/entropy_src/rtl/entropy_src_core.sv
index 3ab22c3..e2eccd8 100755
--- a/hw/ip/entropy_src/rtl/entropy_src_core.sv
+++ b/hw/ip/entropy_src/rtl/entropy_src_core.sv
@@ -376,9 +376,9 @@
 
 
   // set the interrupt sources
-  assign event_es_fifo_err =
+  assign event_es_fifo_err = es_enable && (
          (|sfifo_esrng_err) ||
-         (sfifo_esfinal_err);
+         (sfifo_esfinal_err));
 
   // set the err code source bits
   assign hw2reg.err_code.sfifo_esrng_err.d = 1'b1;