Fix xnn linkage issue when building wheels (#7173)

Author: mcr229

CMakeLists.txt

@@ -742,9 +742,9 @@ if(EXECUTORCH_BUILD_PYBIND)
   endif()
 
   if(EXECUTORCH_BUILD_XNNPACK)
-    # need to explicitly specify XNNPACK here otherwise uses XNNPACK symbols
-    # from libtorch_cpu
-    list(APPEND _dep_libs xnnpack_backend XNNPACK)
+    # need to explicitly specify XNNPACK and microkernels-prod
+    # here otherwise uses XNNPACK and microkernel-prod symbols from libtorch_cpu
+    list(APPEND _dep_libs xnnpack_backend XNNPACK microkernels-prod)
   endif()
 
   # compile options for pybind