net: wimax: Remove of unused 'rfkill_input' pointer

Seems like this was not cleaned during the 'rfkill: rewrite' checkin
19d337df.

Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Acked-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>