Input: elants - remove unused axes

Driver only ever reports MT events and input_mt_init_slots() sets up
emulated axes already.  Clear the capabilities not generated directly
and move MT axes setup, so they are visible by input_mt_init_slots().

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/d5eee8cd305adb144a11264d70da94f7b6570366.1587923061.git.mirq-linux@rere.qmqm.pl


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>