bpo-41983: add availability info to socket docs (GH-27519)

* add availability info to AF_PACKET section

* add availability for AF_QIPCRTR as well

Author: akulakov

Doc/library/socket.rst

@@ -197,11 +197,15 @@ created.  Socket addresses are represented as follows:
   - *addr* - Optional bytes-like object specifying the hardware physical
     address, whose interpretation depends on the device.
 
+   .. availability:: Linux >= 2.2.
+
 - :const:`AF_QIPCRTR` is a Linux-only socket based interface for communicating
   with services running on co-processors in Qualcomm platforms. The address
   family is represented as a ``(node, port)`` tuple where the *node* and *port*
   are non-negative integers.
 
+   .. availability:: Linux >= 4.7.
+
   .. versionadded:: 3.8
 
 - :const:`IPPROTO_UDPLITE` is a variant of UDP which allows you to specify