iwlwifi: bump required firmware API version for 3160/7260

commit a2d0909a687b4d250cc2b7481072e361678745ba upstream.

As the firmware API has changed significantly and we don't
have support code for the old APIs, bump the version to be
able to release the version 7 API firmware. Unfortunately
this means that the driver in 3.9 and 3.10 can't work, but
that's still better than crashing the device/driver there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>