Input: remove unneeded variable in input_inhibit_device()

Remove unneeded variable used to store return value.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Link: https://lore.kernel.org/r/20220419064255.2563333-1-deng.changcheng@zte.com.cn


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