iwl4965: set power mode early

If device was put into a sleep and system was restarted or module
reloaded, we have to wake device up before sending other commands.
Otherwise it will fail to start with Microcode error.

Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>