staging: cxt1e1: remove unneeded mkret() calls

The mkret() change a value of error from positive to
negative. This patch is modified to return negative value
when it failed. It doesn't need to call with function
for changing from positive to negative.

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