Input: ar1021 - fix typo in preprocessor macro name

Fix spelling mistake.

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Link: https://lore.kernel.org/r/1573211947-660-1-git-send-email-f.suligoi@asem.it


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