kcms/libkwindevices: use function value instead of function
Prop p.value is a function. We should call set on its return value, instead of on the function pointer.
Not sure why the old code actually compiles, but a gentoo user is reporting that build is failing with
.../plasma-desktop-6.1.4/kcms/libkwindevices/inputdevice.h:171:19: error: reference to non-static member function must be called
171 | set(p.value);