staging: cxt1e1: fix checkpatch error 'assignment in if condition'

checkpatch.pl error in linux.c:
 ERROR: do not use assignment in if condition

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