sw/kelvin: add test target for newly added mul op for Kelvin

Add the kelvin_test target for the recently added mul op for
completeness. Verified all tests passed.

Change-Id: I94f00c9eed9d650bb76cf3a05d1f085316765eb2

tests/tflm/BUILD

diff --git a/tests/tflm/BUILD b/tests/tflm/BUILD
index 183451f..3834394 100644
--- a/tests/tflm/BUILD
+++ b/tests/tflm/BUILD
@@ -102,6 +102,23 @@
 )
 
 kelvin_test(
+    name = "mul_test",
+    srcs = [
+        "@tflite-micro//tensorflow/lite/micro/kernels:mul_test.cc",
+    ],
+    hw_test_size = "large",
+    deps = [
+        "//crt",
+        "@tflite-micro//tensorflow/lite/c:common",
+        "@tflite-micro//tensorflow/lite/kernels/internal:tensor",
+        "@tflite-micro//tensorflow/lite/micro:micro_utils",
+        "@tflite-micro//tensorflow/lite/micro:test_helpers",
+        "@tflite-micro//tensorflow/lite/micro/kernels:kernel_runner",
+        "@tflite-micro//tensorflow/lite/micro/testing:micro_test",
+    ],
+)
+
+kelvin_test(
     name = "pooling_test",
     srcs = [
         "@tflite-micro//tensorflow/lite/micro/kernels:pooling_test.cc",