Input: xpad - spelling fixes for "Xbox"

The Linux kernel is notorious for misspelling X-Box, X-box, XBox or XBOX;
the official spelling is actually just Xbox. Plain and simple.

Tried to respect the existing notes but still following the style guide.
No functional changes intended. This only affects ancillary parts.

Signed-off-by: Ismael Ferreras Morezuelas <swyterzone@gmail.com>
Link: https://lore.kernel.org/r/401b1d94-1348-15fd-b48f-a80e8885c7a4@gmail.com


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