acer-wmi: Only update rfkill status for associated hotkey events

BugLink: http://bugs.launchpad.net/bugs/771758

acer-wmi is indiscriminately using the device state from hotkey
events to update the various rfkill states. On the Aspire 1830 this
can result in a soft block on the wlan when the touchpad hotkey is
pressed, as it is reporting a non-zero device state that does not
reflect the wireless status. To fix this, only update rfkill states
when a wlan or bluetooth hotkey is pressed.

(backported from commit 92530664bbe5a13aede4a8763459bbe560ad9221 upstream)

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>