gpio: cdev: Avoid NULL dereference in linehandle_create()

In the Linux kernel, the following vulnerability has been resolved:

gpio: cdev: Avoid NULL dereference in linehandle_create()

In linehandle_create(), there is a statement like this:

retain_and_null_ptr(lh);

Soon after, there is a debug printout that dereferences "lh", which

will crash things.

Avoid the crash by using handlereq.lines, which is the same value.