Input: uinput - rework ABS validation

Rework the uinput ABS validation to check passed absinfo data immediately,
but do ABS initialization as last step in UI_DEV_CREATE. The behavior
observed by user-space is not changed, as ABS initialization was never
checked for errors.

With this in place, the order of device initialization and abs
configuration is no longer fixed. Userspace can initialize the device and
afterwards set absinfo just fine.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>