iwlwifi: remove input device and fix rfkill state

This patch fixes the iwlwifi rfkill. It removes the input device from iwl3945,
adds support for RFKILL_STATE_HARD_BLOCKED and calls rfkill_force_state() to
update the state rather than accessing it directly.
The calls to iwl|iwl3945_rfkill_set_hw_state() had to be moved because
rfkill_force_state() cannot be called from an atomic context.
Tested on iwl3945 and seems to work fine.

Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Ivo van Doorn <ivdoorn@gmail.com>
Cc: Fabien Crespel <fcrespel@gmail.com>
Cc: Zhu Yi <yi.zhu@intel.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>