Remove Xlnk reference in microblaze notebooks (#1151)

boards/Pynq-Z1/base/notebooks/microblaze/microblaze_programming.ipynb

@@ -179,7 +179,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Finally we can pass a `void` pointer which will allow the Microblaze to directly access the memory of the host processing system for transferring large quantities of data. In Python these blocks of memory should be allocated using the `Xlnk.cma_array` function and it is the responsibility of the programmer to make sure that the Python and C code agree on the types used."
+    "Finally we can pass a `void` pointer which will allow the Microblaze to directly access the memory of the host processing system for transferring large quantities of data. In Python these blocks of memory should be allocated using the `pynq.allocate` function and it is the responsibility of the programmer to make sure that the Python and C code agree on the types used."
    ]
   },
   {
@@ -217,10 +217,9 @@
     }
    ],
    "source": [
-    "from pynq import Xlnk\n",
-    "allocator = Xlnk()\n",
+    "from pynq import allocate\n",
     "\n",
-    "buffer = allocator.cma_array(shape=(1024 * 1024), dtype='i4')\n",
+    "buffer = allocate(shape=(1024 * 1024), dtype='i4')\n",
     "buffer[:] = range(1024*1024)\n",
     "\n",
     "big_sum(buffer, len(buffer))"