iwl4965: set power mode early

commit eca396d7a5bdcc1fd67b1b12f737c213ac78a6f4 upstream.

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.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
[bwh: Backported to 3.2: adjust filename, context, naming]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>