Input: xpad - add support for Amazon Game Controller

The Amazon Luna controller (product name "Amazon Game Controller") behaves
like an Xbox 360 controller when connected over USB.

Signed-off-by: Matt Reynolds <mattreynolds@chromium.org>
Reviewed-by: Harry Cutts <hcutts@chromium.org>
Link: https://lore.kernel.org/r/20210429103548.1.If5f9a44cb81e25b9350f7c6c0b3c88b4ecd81166@changeid
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>