gpio: sim: fix a memory leak

commit 79eeab1d upstream.

Fix an inverted logic bug in gpio_sim_remove_hogs() that leads to GPIO
hog structures never being freed.

Fixes: cb8c474e ("gpio: sim: new testing module")
Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>