bindings: cxx: remove superfluous std::move

bindings: cxx: remove superfluous std::move

There is no need to use std::move on an r-value (e.g.
std::move(gpiod::chip())). Similarly, there is no need to use std::move
for returning a local variable as in:

T foo()
{
    U local;
    return std::move(local);
}

Not only it doesn't help, it actually inhibits named return value
optimization.

See e.g. https://isocpp.org/blog/2013/02/no-really-moving-a-return-value-is-easy-stackoverflow

Signed-off-by: David Kozub <zub@linux.fjfi.cvut.cz>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>