Input: analog - use get_cycles() on PPC

The analog joystick driver spits a warning at us:

  drivers/input/joystick/analog.c:176:2: warning: #warning Precise timer
  not defined for this architecture.

PPC has get_cycles() so use that.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>