staging: atomisp: remove useless #ifdef ISP2401 on top of atomisp_cmd.c

There is no reason to have "#ifdef ISP2401" condition
on top of atomisp_cmd.c file

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>