Input: keyboard - "keycode & KEY_MAX" changes some keycode values

For exmaple, keycode: KEY_OK(0x160) is changed by "and" operation with
KEY_MAX(0x2ff) to KEY_KPENTER(96).

Signed-off-by: Andrew Liu <andrew.liu200917@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>