net: rfkill: gpio: hard-code the gpio names

There is no need to dynamically generate the names. This
will fix a static checker warning..

net/rfkill/rfkill-gpio.c:144 rfkill_gpio_probe()
    warn: variable dereferenced before check 'rfkill->name'

Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>