docs/library/machine: Remove conditionals in machine class index.

The machine module should be standard across all ports so should have the
same set of classes in the docs.  A special warning is added to the top of
the machine.SD class because it is not standardised and only available on
the cc3200 port.

docs/library/machine.SD.rst

@@ -4,6 +4,11 @@
 class SD -- secure digital memory card
 ======================================
 
+.. warning::
+
+   This is a non-standard class and is only available on the cc3200 port.
+
+
 The SD card class allows to configure and enable the memory card
 module of the WiPy and automatically mount it as ``/sd`` as part
 of the file system. There are several pin combinations that can be

docs/library/machine.rst

@@ -140,31 +140,16 @@ Constants
 Classes
 -------
 
-.. only:: not port_wipy
-
- .. toctree::
+.. toctree::
    :maxdepth: 1
 
    machine.Pin.rst
    machine.Signal.rst
-   machine.UART.rst
-   machine.SPI.rst
-   machine.I2C.rst
-   machine.RTC.rst
-   machine.Timer.rst
-   machine.WDT.rst
-
-.. only:: port_wipy
-
- .. toctree::
-   :maxdepth: 1
-
-   machine.Pin.rst
-   machine.UART.rst
-   machine.SPI.rst
-   machine.I2C.rst
-   machine.RTC.rst
-   machine.Timer.rst
-   machine.WDT.rst
    machine.ADC.rst
+   machine.UART.rst
+   machine.SPI.rst
+   machine.I2C.rst
+   machine.RTC.rst
+   machine.Timer.rst
+   machine.WDT.rst
    machine.SD.rst