Input: docs - note that MT-A protocol is obsolete

Everyone should be using multitouch protocol B (slotted) now.

Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/input/multi-touch-protocol.rst

···
 devices capable of tracking identifiable contacts (type B), the protocol
 describes how to send updates for individual contacts via event slots.
 
+.. note::
+   MT potocol type A is obsolete, all kernel drivers have been
+   converted to use type B.
 
 Protocol Usage
 --------------
···
 
 For type A devices, all finger data bypasses input filtering, since
 subsequent events of the same type refer to different fingers.
-
-For example usage of the type A protocol, see the bcm5974 driver. For
-example usage of the type B protocol, see the hid-egalax driver.
 
 .. [#f1] Also, the difference (TOOL_X - POSITION_X) can be used to model tilt.
 .. [#f2] The list can of course be extended.