input: remove Linux joystick support

Why did this exist in the first place? Other than being completely
useless, this even caused some regressions in the past. For example,
there was the case of a laptop exposing its accelerometer as joystick
device, which led to extremely fun things due to the default mappings of
axis movement being mapped to seeking.

I suppose those who really want to use their joystick to control a media
player (???) can configure it as mouse device or so.

DOCS/man/mpv.rst

@@ -32,7 +32,7 @@ INTERACTIVE CONTROL
 ===================
 
 mpv has a fully configurable, command-driven control layer which allows you
-to control mpv using keyboard, mouse, joystick or remote control (there is no
+to control mpv using keyboard, mouse, or remote control (there is no
 LIRC support - configure remotes as input devices instead).
 
 See the ``--input-`` options for ways to customize it.

DOCS/man/options.rst

@@ -2358,12 +2358,6 @@ Input
     driver. Necessary to use the OSC, or to select the buttons in DVD menus.
     Support depends on the VO in use.
 
-``--input-joystick``, ``--no-input-joystick``
-    Enable/disable joystick support. Disabled by default.
-
-``--input-js-dev``
-    Specifies the joystick device to use (default: ``/dev/input/js0``).
-
 ``--input-media-keys=<yes|no>``
     (OS X only)
     Enable/disable media keys support. Enabled by default (except for libmpv).

DOCS/mplayer-changes.rst

@@ -241,7 +241,6 @@ Command Line Switches
     ``-noar``                   ``--no-input-appleremote``
     ``-noautosub``              ``--no-sub-auto``
     ``-noconsolecontrols``      ``--no-input-terminal``
-    ``-nojoystick``             ``--no-input-joystick``
     ``-nosound``                ``--no-audio``
     ``-osdlevel``               ``--osd-level``
     ``-panscanrange``           ``--video-zoom``, ``--video-pan-x/y``